Siege of Capua (1734)

Following the outbreak of the War of the Polish Succession in the fall of 1733, and news that Bourbon allies France and Spain were planning operations against the kingdoms of Naples and Sicily, Habsburg military and political leaders began planning the defense of Naples against the expected invasion. Hampered by a lack of resources, Marshal Otto Ferdinand von Abensberg und Traun and the Count of Caraffa disagreed on how to best defend Naples. Caraffa wanted to minimally garrison the country's fortresses and concentrate Austrian forces into a single army that could either avoid or force confrontation with the Spanish, while Traun, whose opinion prevailed, wanted to strongly garrison the fortresses and force the Spanish to besiege them.^[1]

Major garrisons were placed at Pescara and Gaeta, and Traun himself took command of 3,500 men and occupied the fortress at Capua, near the northwestern border between the kingdom and the Papal States.^[2] Caraffa was responsible for the defense of the city of Naples and the safety of the Austrian viceroy Giulio Visconti Borromeo Arese.

The army of Charles of Parma, numbering about 21,000, marched south from Tuscany where it had been assembled, and reached the northern border of Naples on 28 March 1734.^[3][4] Traun had taken most of the Capua garrison, and constructed a fortified line at Mignano, at which he expected conflict with the Spanish forces.^[2] However, on 30 March, the Spanish, aided by sympathetic locals, sent 4,000 troops through narrow mountain passes, threatening to flank Traun's position. When Traun learned of this, he ordered a precipitous retreat to Capua, abandoning armaments and camp equipment along the way. The Spanish then proceeded southward toward Naples, bypassing Capua, and entered the city on 10 May after securing the surrender of its fortresses. About 6,000 troops were stationed to blockade Capua cutting off its communications and access to the land for provisions.^[5]

While Charles' army was marching south, a Spanish fleet had landed forces on the islands of Ischia and Procida in the Bay of Naples.^[6] Austrian garrisons from these islands had been brought to the mainland, where they joined the garrison at Capua (before it was blockaded), raising the size of Traun's garrison to about 6,000. The Austrians were hoping to be relieved by the forces of Florimund Mercy in northern Italy, but these were occupied with the Franco-Sardinian army.

Following the destruction of the Austrian army at Bitonto in May, Spanish forces turned to besiege the three remaining Austrian outposts: Pescara, Gaeta, and Capua. Pescara was the first to surrender, on 29 July, with Gaeta surrendering in August.^[7] Charles was then able to detach troops for the conquest of Sicily, and focus the remaining troops on Capua.

The fortress of Capua was a substantial construction, although it had not been maintained well in the years immediately preceding this conflict. It had numerous weaknesses, the principle of which were:

• The water supply;
• The poorly-bastioned Naples gate;
• The landscape to the south and west, which was dotted with groves of olive and fruit trees.

The garrison, under the command of Marshal Traun, consisted of 6,000 men, including 10 battalions of infantry from the regiments of Heister, Göldlin, O'Nelly, Carl Lothringen, and Schmettau, 6 grenadier companies, and companies of horseless cuirassiers from the regiments of Pignatelli and Kokoržowa.^[8]

Traun may also have benefited from a long-standing friendship with Count Marsillac, the commander of the besieging forces. The two had fought together in previous campaigns, and even shared the same tent on occasion.^[9]