In June 1589, an English sailor George Beeston arrived in the Forth and Delny was sent to greet him.[22] In October Delny was in the retinue which accompanied James VI to Norway and Denmark to collect his future Queen, Anne of Denmark.[23] James Melville of Halhill mentions that Delny did not sail in the king's ship, but in one of three other ships, along with Lewis Bellenden, John Carmichael, the Provost of Lincluden, George Home, James Sandilands, and Peter Young.[24]
After the royal wedding at Oslo, Colonel William Stewart sailed back to Edinburgh with instructions for the royal homecoming in the spring, and news of arguments between Chancellor of Scotland, John Maitland of Thirlestane, and the Earl Marischal and his kinsman William Keith of Delny, over precedence and the Queen's dowry.[25] James VI ordered Chancellor Maitland to give jewels to Christian IV and his mother Sophie of Mecklenburg and other royals. These gifts included four great table diamonds and two great rubies set in gold rings which Delny had brought to Denmark.[26] There was discussion whether the queen's dowry money should be brought home untouched to Scotland, or whether the Earl Marischal, Lord Dingwall and Delny should be recompensed.[27] James VI gave Delny 830 Danish dalers from the dowry for clothes received in Denmark.[28]
During their time in Denmark, the king sacked Delny as keeper of the wardrobe, allegedly for appearing in richer clothing than himself, and appointed Sir George Home in his stead.[29] In the days before Delny lost his place, Robert Douglas, Provost of Lincluden on 4 April 1590 wrote "Sir William Keith is lyke to be casin, and to tyne his offices, credit and all."[30] A correspondent of Francis Walsingham wrote on 5 April 1590 that the Chancellor, John Maitland of Thirlestane, aimed to discredit the Earl Marischal and Delny, but Delny was "wonderfully well beloved" and had "ever worn his sword on the right and true side".[31] Archibald Douglas suggested Keith's allies were a threat to Maitland, and a royal guard raised by Sir John Carmichael was chiefly to protect the Chancellor.[32]
In the summer of 1590, Delny fell under suspicion of conspiring with the Earl Marischal and Alexander Home, 6th Lord Home to murder the Lord Chancellor. When, in July, the Earl Marischal was arrested, he sought the protection of Francis Stewart, 5th Earl of Bothwell. In the last week of July, Delny stayed at the house of Dorothea Stewart, Countess of Gowrie, near Holyrood Palace, hoping to regain the king's favour.[33] Possibly unaware of his increasing difficulties, Christian IV of Denmark wrote to James VI on 3 August 1590 interceding for Delny's return to favour.[34]
James VI became angry about discussions that Delny might marry the Countess of Gowrie, and would have made him appear before the Privy Council in July 1591.[35] The English ambassador Robert Bowes noted in July 1591 that Delny "lay in bed" once or twice at Morham Tower with the owner, the rebellious Bothwell.[36] When news that Delny had joined Bothwell's retinue reached the king, his estates were forfeited. He subsequently fled into exile with Bothwell.[37]
Delny regained royal favour in June 1592, apparently as a result of the intervention of Anne of Denmark, though he did not recover his office in the wardrobe.[38] In January 1593 he was given the barony of Dingwall, which his kinsman Andrew Keith, Lord Dingwall had resigned. The letter of gift thanked Delny for his services to the king including a role in the proxy marriage to Anne of Denmark in 1589.[39]
Delny became an associate of Ludovick Stuart, 2nd Duke of Lennox. On 6 May 1593 the Duke and 15 friends subscribed to a frivolous legal document swearing to abstain from wearing gold and silver trimmings on their clothes for a year, and defaulters were to pay for a banquet for all of them at John Killoch's house in Edinburgh. This "passement bond" was in part inspired by cheap counterfeit gold and silver thread used in "passements great or small, plain or à jour, bissets, lilykins, cordons, and fringes" which quickly discoloured. The signatories included; Lord Home, the Earl of Mar, Lord Spynie, the Master of Glamis, Sir Thomas Erskine, Walter Stewart of Blantyre, David Seton of Parbroath, and Sir George Home.[40]
In 1593 Delny as chamberlain of the lands of Ross and Ardmannoch delivered his account of royal income to the comptroller, David Seton of Parbroath.[41] In February James VI confirmed his grant of the barony of Delny and gave him the patronage of three parish churches, noting his devotion to spreading the Gospel.[42]
In October 1593 Delny was in London and met secretly with Anthony Bacon, a follower of the Earl of Essex. Bacon wrote to Delny that Essex would accept a letter from James VI at Richmond Palace and he should burn the letter and not tell anybody about their meeting.[43]
Delny wrote to James Hudson in March 1594. Hudson had been one of the king's viola players, the four Hudson brothers, and was now a resident diplomatic agent in London. Delny wrote that he had read Hudson's previous three letters to the king. Both James VI and Anne of Denmark had told him that John Wemyss of Logie had no diplomatic mission from them. Delny urged Hudson to be careful in the king's affairs, not to upset the delicate issue of the succession. After other matters, Delny wished Hudson to convey his thanks to Sir Roger Williams and Fulke Greville. Hudson made a copy of this letter for Bacon and Essex.[44]
In 1594 Delny carried invitations to the baptism and tournament at Stirling Castle for Prince Henry to the Dutch Republic.[45] Sir James Melville of Halhill said he was not suited to the role because he could not speak French, Latin, or Flemish.[46] His partner in this embassy was Captain William Murray of Pitcarleis, Provost of St Andrews. They were instructed to confirm previous peace treaties and to give good report of Adrian Damman van Bijsterveld, the resident diplomat of the States General at the court of Scotland, and ask that Scots soldiers serving in the Eighty Years' War be paid.[47]
The ambassadors from the Dutch Republic at the baptism, Walraven III van Brederode (1547–1614) and Jacob Valke, treasurer of Zeeland, brought Prince Henry a gift of a guaranteed income. Delny was appointed chamberlain of the Prince's household and collector of this money on 1 October 1594.[48] Delny lost this role in 1595 when the Earl of Mar, as guardian of the Prince at Stirling Castle, was given charge of the Dutch income.[49] Delny left the round box with the letter of gift in Edinburgh with John Gourlay, and in 1601 Gourlay delivered it to George Home of Spott.[50]
Delny left Edinburgh for Venice on 4 October 1595.[51] He went first to London, then embarked with Henry Hawkyns, a nephew of Christopher Yelverton, a companion recommended by Anthony Bacon. Delny wrote to Bacon in November offering his services to Queen Elizabeth against Spain. Delny said he would have delivered James VI's letter and message in person to Essex, if the earl had been in London, requesting hawks and also asking that the rebel Francis Stewart, 5th Earl of Bothwell should not be welcomed in England. Bacon should give the answers to the king's requests to Thomas Foulis.[52] Delny was in Venice to canvas support for James VI.[53] He explained to the senators of Venice that he was not an ambassador, but came to learn the language and further the king's private business.[54]
Delny wrote to Foulis from Padua, and mentioned the secure way that he had folded the king's letter, and disguised the address. Such practices are known as "letterlocking" a term first coined by Jana Dambrogio:
I close his majesties lettir, swa that giff he taik not ane knyff and cott it owt, it will ryff; lykwys I have cloissit roidlie, that it be not brokin owt or kend, sua exquisse my roidnes lowrd in this.
I close his majesty's letter so that if he does not use a knife and cut it open, it will tear, also I have sealed it rudely, so it might not be picked out and known, so exuse my rough rudeness in this.[55]
In April 1597 James VI asked Delny to correspond with Venice, to bolster support for his accession to the throne of England.[56]
A legal case mentions his death and the cessation of payments owed to creditor in 1599.[57] A charter of July 1601 mentions his death, and an earlier note in the royal wardrobe accounts made in 1599 by Thomas Foulis and Robert Jousie also refers to his decease. He had three children, Sara, and two sons, both called William. His property passed to his brother, John Keith of Ravenscraig.[58]
Delny owed the banker Thomas Foulis £6248 Scots. His brother and heir, John Keith of Craig was liable to repay the debt to James Foulis of Colinton.[59] The debt was probably connected with the royal wardrobe. In 1605 the debts due to the Master of Gray were examined, including £1000 given to Delny as Master of the Wardrobe.[60]
Keith used a seal in 1594 quartering the Keith arms used by the Earl Marischal and Andrew Keith, Lord Dingwall, (argent a chief paly of or and gules), with 2nd three cushions in a flowered tressure, and 3rd a bend between three cross crosslets and three mullets.[61]