vernor of Flushing, gave him the command of a company of foot there (July 1614), and he became colonel of a regiment in the Dutch service two years later (May 1616). He represented Wilton in the parliament of 1614, Kent in that of 1621, and Monmouthshire in 1624 and 1625. After 1618 he was styled Lord Lisle, and succeeded his father as Earl of Leicester on 13 July 1626 (Doyle).
In 1616 Sidney married Dorothy Percy, daughter of Henry, ninth earl of Northumberland, a marriage which led to a close friendship between Algernon Percy, tenth earl, and Sidney, and greatly influenced his subsequent political career (Fonblanque, Annals of the House of Percy, ii. 341). Incidentally it also led to a violent quarrel between Sidney and James Hay, viscount Doncaster, who had married Lucy Percy, which is related at length by Sidney (Collins, i. 121, ii. 371).
Leicester's first public employment was his embassy to Christian IV of Denmark and to the Duke of Holstein (September to November 1632). The exact journal of his embassy, with observations on the king, court, and country which Leicester drew up, Collins promises but fails to print (Sydney Papers, i. 128, ii. 370). James Howell [q. v.], who was Leicester's secretary, gives an account of the incidents of the mission, describing the ‘stoutness’ with which Leicester drank with the Danish king, and praising the swiftness with which he despatched his diplomatic business (Howell, Letters, ed. Jacobs, pp. 294–305, 651, 675).
Leicester's second public employment was his embassy to France, whither he was sent in May 1636. He remained there till May 1641, returning to England for five months in April 1639. His despatches during this mission are printed at length, and contain an interesting picture of the French court; but as the object of Charles I was to obtain French aid in the recovery of the palatinate without giving any adequate return to France, the results of the embassy were of the most trifling description (Collins, i. 129, ii. 374–662; Gardiner, History of England, viii. 61–3). On his return to England Leicester was admitted to the privy council (5 May 1639), and in the following November Strafford, Northumberland, and the queen urged Charles to appoint him secretary of state in place of Sir John Coke. The appointment would have been popular. ‘Leicester, like Northumberland, belonged to that section of the nobility which was distinctly protestant without being puritan, and which was disposed to support the king against rebellion without favouring an arbitrary exertion of the prerogative.’ But Leicester, by his conduct towards French protestantism, had earned for himself the reputation of puritanism, and Laud's hostility was fatal to his candidature (ib. ix. 85; Collins, ii. 618, 623; Blencowe, p. 261; Clarendon, Rebellion, ed. Macray, iv. 41 n.)
On 14 June 1641 Leicester was appointed lord-lieutenant of Ireland in succession to Strafford (Doyle, ii. 348; Gardiner, x. 47). He delayed to start for Ireland, and the outbreak of the Irish rebellion in October 1641, followed by the war between king and parliament, prevented him from going later. With the difficulties of his position he was hardly fitted to cope. Clarendon characterises him as ‘a man of great parts, very conversant in books, and much addicted to the mathematics; and though he had been a soldier … and was afterwards employed in several embassies … was in truth rather a speculative than a practical man, and expected greater certitude in the consultation of business than the business of this world is capable of.’ Both parties claimed his obedience, so that ‘the earl's condition was very slippery and almost impossible to be safely managed by the most dexterous person’ (Clarendon, vi. 304, 387). ‘The parliament,’ wrote Leicester to the Countess of Carlisle, ‘bids me go presently, the king commands me to stay till he despatch me. The supplies of the one and the authority of the other are equally necessary. I know not how to obtain them both, and am more likely to have neither. … I am suspected and distrusted of either side’ (Blencowe, p. xxi, 25 Aug. 1642). On 9 Sept. 1642 he wrote to the Earl of Northumberland, explaining that the king's delay to provide him with his instructions, in spite of repeated petition for them, had prevented him from repairing to Ireland, and that the king's officers had seized the draught-horses which he had provided for the service of Ireland. The publication of this letter gave great offence, which increased still more when Leicester, in spite of the king's command, showed his instructions from the king to the parliament's committee. Finally, on 29 Nov. 1642, just as Leicester was about to embark, the king forbade him to go and summoned him to Oxford (Collins, i. 138; Gardiner, Great Civil War, i. 119; Clarendon, v. 304; Carte, Ormonde, ii. 23, 288). There Leicester remained for the next year in a very uncomfortable position. ‘Though he was of the council and sometimes present, he desired not to have any part of the business, and lay under many reproaches and jealousies which he deserved not; for he was a man of honour