Empire

The Delian League was a confederacy of Greek city-states, numbering between 150 and 330,^[16] founded in 478 BC^[17] under the hegemony of Athens, whose purpose was to continue fighting the Persian Empire after the Greek victory in the Battle of Plataea at the end of the Second Persian invasion of Greece.^[18] The League functioned as a dual—offensive and defensive—alliance (symmachia) of autonomous states, similar to its rival association, the Peloponnesian League led by Sparta.^[19] The League's modern name derives from its official meeting place, the island of Delos, where congresses were held within the sanctuary of the Temple of Apollo;^[20] contemporary authors referred to the organization simply as "the Athenians and their Allies".^[21][22]

While Sparta excelled as Greece's greatest power on land, Athens turned to the seas, becoming the dominant naval power of the Greek world. Following Sparta's withdrawal from the conflict with Persia, Athens took the lead of the Hellenic alliance accompanied by several states around the Aegean and the Anatolian coast.^[23][24] The Delian League was formed as an anti-Persian defensive association of equal city-states seeking protection under Athens, as the latter wished to extend its support towards the Ionian Greek colonies of Anatolia.^[20][25] The alliance held an assembly of representatives in order to shape its policy, while members swore an oath of loyalty to the coalition.^[24] By the mid-fifth century BC, it had developed into a naval imperial power, conventionally called the Athenian Empire, where Athens established complete dominion and the allies became increasingly less autonomous.^[20] The League led by Cimon, successfully accomplished its principal strategic goal by decisively expelling the remaining Persian forces from the Aegean. As a result, Persia would cease to pose a major threat to Greece for the following fifty years.^[26]

From its inception, Athens became the League's biggest source of military power, while more and more allies preferred to pay their dues in cash. Athens began to use the League's funds for its own purposes, like the reinforcement of its naval supremacy, which led to conflicts with the less powerful allies, at times culminating in rebellions, like that of Thasos in 465 BC.^[27] The League's treasury initially stood in Delos until, in a symbolic gesture,^[28] Pericles moved it to Athens in 454 BC.^[29] By 431 BC, the threat that the League presented to Spartan hegemony, combined with Athens's heavy-handed administration, prompted the outbreak of the Peloponnesian War; the League was dissolved upon the war's conclusion in 404 BC^[25] under the direction of Lysander. Witnessing Sparta's growing hegemony in the first half of the 4th century BC, Athens went on to partly revive the alliance, this time called the Second Athenian League, reestablishing its naval dominance in the eastern Mediterranean.^[30]

The Roman Empire was a state that dominated the Mediterranean and much of Europe, Western Asia, and North Africa during the classical period. The Roman Republic had previously conquered most of these territories, which later came under permanent single-person rule following Octavian's rise to power and the establishment of the Augustan Principate in 27 BC. By the late 3rd century AD, the empire had been divided many times. The Western Roman Empire collapsed in 476 AD, whereas the Eastern Roman Empire (also known as the Byzantine Empire) persisted until the fall of Constantinople in 1453.

By 100 BC, the city of Rome had expanded its rule from the Italian peninsula to most of the Mediterranean and beyond. However, it was severely destabilised by civil wars and political conflicts, which culminated in the victory of Octavian over Mark Antony and Cleopatra at the Battle of Actium in 31 BC, and the subsequent conquest of the Ptolemaic Kingdom in Egypt. In 27 BC, the Roman Senate granted Octavian overarching military power (imperium) and the new title of Augustus, marking his accession as the first Roman emperor. The vast Roman territories were organized into senatorial provinces, governed by proconsuls who were appointed by lot annually, and imperial provinces, which belonged to the emperor but were governed by legates.

The first two centuries of the Empire saw unprecedented stability and prosperity known as the Pax Romana (lit. 'Roman Peace'). Rome reached its greatest territorial extent under Trajan (r. 98–117 AD), but increasing trouble and decline began under Commodus (r. 180–192). In the 3rd century, the Empire underwent a 50-year crisis that threatened its existence due to civil war, plagues and barbarian invasions. The Gallic and Palmyrene empires broke away and a series of short-lived emperors led the Empire, which was later reunified under Aurelian (r. 270–275). The civil wars ended with the victory of Diocletian (r. 284–305), who set up two different imperial courts in the Greek East and Latin West. Constantine the Great (r. 306–337), the first Christian emperor, moved the imperial seat from Rome to Byzantium in 330, and renamed it Constantinople. The Migration Period, involving large invasions by Germanic peoples and the Huns, led to the decline of the Western Roman Empire. With the fall of Ravenna to the Germanic Herulians and the deposition of Romulus Augustus in 476 by Odoacer, the Western Empire finally collapsed. The Byzantine (Eastern Roman) Empire survived for another millennium with Constantinople as its sole capital, until the city's fall in 1453.^[a]

Due to the Empire's extent and endurance, its institutions and culture had a lasting influence on the development of language, religion, art, architecture, literature, philosophy, law, and forms of government across its territories. The rediscovery of classical science and technology (which formed the basis for Islamic science) in medieval Europe contributed to the Scientific Renaissance and Scientific Revolution. Rome's republican institutions have influenced the Italian city-state republics of the medieval period, the early United States, and modern democratic republics.

The Achaemenid Empire^[b] (/əˈkiː.mə.nɪd/, ə-KEE-mə-nid; Old Persian: 𐎧𐏁𐏂, Xšāça, lit. 'The Empire'^[35] or 'The Kingdom'^[36]) was an ancient Iranian empire founded by Cyrus the Great of the Achaemenid dynasty in 550 BC. At peak, its territorial extent was roughly 5.5 million square kilometres (2.1 million square miles), making it the largest empire of its time. Based in the Iranian plateau, it stretched from the Balkans and Cyrenaica in the west to the Indus Valley in the east, including Anatolia, Cyprus, Mesopotamia, the Levant, the South Caucasus, parts of Eastern Arabia, and large parts of Central Asia.^[37][38][39]

By the 7th century BC, the region of Persis, located in the southwestern part of the Iranian plateau, had been settled by Persian people.^[40] From Persis, Cyrus rose and defeated Media, Lydia, and the Neo-Babylonian Empire, thus marking the establishment of a new imperial polity in the ancient Near East. The empire expanded rapidly, but was repulsed from Scythia in 513 BC and from Greece in 492–490 BC and 480–479 BC.

In 330 BC, amidst a Greek military campaign that began in 336 BC, the Achaemenid Empire was conquered in its entirety by Alexander the Great, who annexed it to his Macedonian Empire.^[41][38] Upon Alexander's death, which sparked the beginning of the Hellenistic period in 323 BC, the majority of the former Achaemenid Empire's territories came under the rule of the Seleucid Empire and the Ptolemaic Kingdom. Almost a century later, Iranian elites in the central plateau successfully reclaimed power from the Seleucids and established the Parthian Empire, which existed for nearly half a millennium before being succeeded by the Iranian Sasanian Empire.^[40]

In the modern era, the Achaemenid Empire has been recognized for its centralized bureaucracy and administration; its multicultural policy and religious tolerance, especially under Cyrus; its complex infrastructure projects, such as the Royal Road and an organized postal system; the use of official languages (Persian and Aramaic) across its territories; and the development of a civil service and a large, professional army and navy. Many of these systems were adopted and expanded upon by later empires in the Greco-Roman world and beyond.^[42]

The Mongol Empire was the largest contiguous empire in history. Originating in present-day Mongolia in East Asia, the medieval empire at its height stretched from the Sea of Japan to Eastern Europe, extending northward into Siberia and east and southward into the Indian subcontinent, mounting invasions of Southeast Asia, and conquering the Iranian plateau; and reaching westward as far as the Levant and the Carpathian Mountains.

The empire emerged from the unification of several nomadic tribes in the Mongol heartland under the leadership of Temüjin, known by the title of Genghis Khan (c. 1162–1227), whom a council proclaimed as the ruler of all Mongols in 1206. The empire grew rapidly under his rule and that of his descendants, who sent out invading armies in every direction. The vast transcontinental empire connected the East with the West, and the Pacific to the Mediterranean, in an enforced Pax Mongolica, allowing the exchange of trade, technologies, commodities, and ideologies across Eurasia.

The empire began to split due to wars over succession, as the grandchildren of Genghis Khan disputed whether the royal line should follow from his son and initial heir Ögedei, or from one of his other sons, such as Tolui, Chagatai, or Jochi. The Toluids prevailed after a bloody purge of the Ögedeid and Chagatayid factions, but disputes continued among the descendants of Tolui. The conflict over whether the empire would adopt a sedentary, cosmopolitan lifestyle, or continue its nomadic, steppe-based way of life was a major factor in the breakup.

After Möngke Khan died in 1259, rival kurultai councils simultaneously elected different successors, the brothers Ariq Böke and Kublai Khan, who fought each other in the Toluid Civil War (1260–1264) and dealt with challenges from the descendants of other sons of Genghis.^[43] Kublai successfully took power, but war ensued as he sought unsuccessfully to regain control of the Chagatayid and Ögedeid families. By Kublai's death in 1294, the empire had fractured into four separate khanates or empires, each pursuing its own objectives: the Golden Horde khanate in the northwest, the Chagatai Khanate in Central Asia, the Ilkhanate in Iran, and the Yuan dynasty in China, based in modern-day Beijing.^[44] In 1304, during the reign of Temür, the three western khanates accepted the suzerainty of the Yuan dynasty.^[45][46]

The Ilkhanate was the first to fall, which disintegrated between 1335 and 1353. Next, the Yuan dynasty lost control of the Tibetan Plateau and China proper in 1354 and 1368, respectively, and collapsed after its capital Dadu was taken over by Ming forces. The Genghisid rulers of the Yuan then retreated north and continued to rule the Mongolian Plateau. The regime is thereafter known as the Northern Yuan dynasty, surviving as a rump state until the conquest by the Qing dynasty in the 1630s. The Golden Horde had broken into competing khanates by the end of the 15th century, and its rule on Eastern Europe is traditionally considered to have ended in 1480 with the Great Stand on the Ugra River by the Grand Duchy of Moscow, while the Chagatai Khanate lasted until 1687, or, in the Yarkent Khanate's case, until 1705.

The British Empire comprised the dominions, colonies, protectorates, mandates, and other territories ruled or administered by the United Kingdom and its predecessor states. It began with the overseas possessions and trading posts established by England in the late 16th and early 17th centuries, and colonisation attempts by Scotland during the 17th century.^[47] At its height in the 19th and early 20th centuries, it was the largest empire in history and, for a century, was the foremost global power.^[48] By 1913 the British Empire held sway over 412 million people, 23 per cent of the world population at the time,^[49] and by 1920 it covered 35.5 million km² (13.7 million sq mi),^[50] 24 per cent of the Earth's total land area. The British Parliament was the supreme law-making authority for all the British possessions which made up the Empire.^[51] As a result, its constitutional, legal, linguistic, and cultural legacy is widespread. It was described as "the empire on which the sun never sets", as the sun was always shining on at least one of its territories.^[52]

During the Age of Discovery in the 15th and 16th centuries, Portugal and Spain pioneered European exploration of the world, and in the process established large overseas empires. Motivated by the great wealth these empires generated,^[53] England, France, and the Netherlands began to establish colonies and trade networks in the Americas and Asia. A series of wars in the 17th and 18th centuries with the Netherlands and France left Britain the dominant colonial power in North America. Britain became a major power in the Indian subcontinent after the East India Company's conquest of Mughal Bengal at the Battle of Plassey in 1757.

The American Revolution resulted in Britain losing some of its oldest and most populous colonies in North America by 1783. While retaining control of British North America (now Canada) and territories in and near the Caribbean in the British West Indies, British colonial expansion turned towards Asia, Africa, and the Pacific. After the defeat of France in the Napoleonic Wars (1803–1815), Britain emerged as the principal naval and imperial power of the 19th century and expanded its imperial holdings. It pursued trade concessions in China and Japan, and territory in Southeast Asia. The Great Game and Scramble for Africa also ensued. The period of relative peace (1815–1914) during which the British Empire became the global hegemon was later described as Pax Britannica (Latin for "British Peace"). It also colonised India by defeating the last major imperial dynasty Maratha Empire by 1818 in the Third Anglo-Maratha War. Alongside the formal control that Britain exerted over its colonies, its dominance of much of world trade, and of its oceans, meant that it effectively controlled the economies of, and readily enforced its interests in, many regions, such as Asia and Latin America.^[54] It also came to dominate the Middle East, shaping its modern borders alongside France. Increasing degrees of autonomy were recognised for its white settler colonies, some of which were formally reclassified as dominions by the 1920s. By the start of the 20th century, Germany and the United States had begun to challenge Britain's economic lead. Military, economic and colonial tensions between Britain and Germany were major causes of the First World War, during which Britain relied heavily on its empire. The conflict placed enormous strain on its military, financial, and manpower resources. Although the empire achieved its largest territorial extent immediately after the First World War, Britain was no longer the world's preeminent industrial or military power.

In the Second World War, Britain's colonies in East Asia and Southeast Asia were occupied by the Empire of Japan. Despite the final victory of Britain and its allies, the damage to British prestige and the British economy helped accelerate the decline of the empire. India, Britain's most valuable and populous possession, achieved independence in 1947 as part of a larger decolonisation movement, in which Britain granted independence to most territories of the empire. The Suez Crisis of 1956 confirmed Britain's decline as a global power, and the handover of Hong Kong to China on 1 July 1997 symbolised for many the end of the British Empire,^[55] though fourteen overseas territories that are remnants of the empire remain under British sovereignty. After independence many former British colonies, along with most of the dominions, joined the Commonwealth of Nations, a free association of independent states. Fifteen of these, including the United Kingdom, retain the same person as monarch, currently .

The Russian Empire^[c] was an empire that extended across northern Eurasia from 1721 until the proclamation of the Russian Republic in 1917, forming the final era of Tsarist Russia and the wider Russian monarchy. At its height in the late 19th century, it covered about 22,800,000 km² (8,800,000 sq mi), roughly one-sixth of the world's landmass, making it the third-largest empire in history, behind only the British and Mongol empires.^[56] The 1897 Russian census found a population of 126 million with considerable ethnic, linguistic, religious, and socioeconomic diversity.^[57]

From the 10th to 17th century, the Russian lands were dominated by a noble class known as the boyars, above whom stood the grand prince and later the tsar, an absolute monarch. The groundwork of the empire was laid by Ivan III (r. 1462–1505), who greatly expanded his domain, established a centralized Russian national state, and secured independence from the Great Horde. His grandson, Ivan IV (r. 1533–1584), was the first Russian monarch to be crowned as tsar in 1547. Between 1550 and 1700, the Russian state grew by an average of 35,000 km² (14,000 sq mi) per year.^[58] Peter the Great transformed the tsardom into an empire, and fought wars that turned Russia into a major European power. He moved the capital from Moscow to the new model city of Saint Petersburg, and led a cultural revolution that introduced a modern, scientific, rationalist, and Western-oriented system. Catherine the Great (r. 1762–1796) presided over further Russian expansion by conquest, colonization, and diplomacy, while continuing Peter's policy of modernization. Alexander I (r. 1801–1825) helped defeat the militaristic ambitions of Napoleon and constituted the Holy Alliance, which aimed to restrain the rise of secularism and liberalism across Europe. Russia further expanded to the west, south, and east, strengthening it as a European power. Its victories in the Russo-Turkish wars were checked by defeat in the Crimean War (1853–1856), leading to a period of reform and conquests in Central Asia instead.^[59] Alexander II (r. 1855–1881) initiated major reforms, most notably the 1861 emancipation of all 23 million serfs.^[60] The period also saw major developments in literature, music, and the sciences.^[61]

By the start of the 19th century, Russian territory extended from the Arctic Ocean in the north to the Black Sea in the south, and from the Baltic Sea in the west to Alaska in the east. It colonized Alaska between 1799 and 1867,^[62] and in the early-to-mid 19th century briefly maintained outposts in California. The empire also expanded its control over the Caucasus, most of Central Asia, and parts of Northeast Asia. In the late 19th and early 20th centuries, the empire experienced industrial growth and railway construction, though the country remained largely agrarian.^[63] Severe famines, such as that of 1891–1892, along with resistance to political reform, led to growing unrest and the rise of revolutionary movements.^[64] Following the 1905 Revolution, Nicholas II (r. 1894–1917) authorized the creation of a national parliament, the State Duma, though ultimate power remained with him.^[65]

Russia entered the First World War in 1914 on the side of the Allies. High casualties, military setbacks, and severe food and fuel shortages in the cities led to widespread discontent with the monarchy.^[66] In 1917, mass unrest in Petrograd and army mutinies culminated in the February Revolution, which led to Nicholas II's abdication, the establishment of the Russian Provisional Government, and the proclamation of the Russian Republic. Political instability, continued involvement in the unpopular war, and economic disruption resulted in mass demonstrations against the government in July.^[67] The republic was overthrown in the October Revolution by the Bolsheviks, who proclaimed the Russian Soviet Federative Socialist Republic and signed a treaty that ended Russia's involvement in the war, but who nevertheless were opposed by various factions known collectively as the Whites.^[68][69] After emerging victorious in the Russian Civil War, the Bolsheviks established the Soviet Union across most of the Russian territory; Russia was one of four continental European empires to collapse as a result of World War I, along with Germany, Austria–Hungary, and the Ottoman Empire.^[70]