'the greatest pulpit-monger in England in man's memory … every time, when Master Preston plucked off his hat to Doctor Davenant, the college master, he gained a chamber or study for one of his pupils.' The college buildings were enlarged to provide for the influx of students. He was in the habit of sending those designed for the church to finish their studies with Cotton, now vicar of Boston, Lincolnshire. Meanwhile, Preston's health was suffering, and he was troubled with insomnia. Twice he applied for advice (once in disguise) to William Butler (1535-1618) [q. v.] of Clare Hall, a successful empiric. Butler only told him to take tobacco; on doing so he found his remedy in 'this hot copious fume.'
Preston had now taken orders, and become dean and catechist of Queens'. He began a course of sermons which were to form a body of divinity. Complaints were made to the vice-chancellor that the college chapel was crowded with scholars from other colleges and townsmen. Order was issued excluding all but members of the college. Preston then began an afternoon lecture at St. Botolph's, of which Queens' College is patron. This brought him into conflict with Newcome, commissary to the chancellor of Ely, whose enmity Preston had earned by preventing a match between his pupil. Sir Capel Bedels, and Newcome's daughter Jane. A dispute with Newcome at St. Botolph's delayed the afternoon service; to make room for the sermon, common prayer was for once omitted. Newcome sped to the court at Newmarket to denounce Preston as a nonconformist. The matter came before the heads of houses, and there was talk of Preston's expulsion from the university. At the suggestion of Lancelot Andrewes [q. v.], then bishop of Ely, Preston was directed to declare his judgment regarding forms of prayer in a sermon at St. Botolph's. He acquitted himself so as to silence complaint. Soon afterwards he was summoned to preach before the king at Finchingbrook, near Royston, Cambridgeshire. James highly approved his argument against the Arminians; he would have shown him less favour had he known that Preston was the author of a paper against the Spanish match, circulated with much secrecy among members of the House of Lords. He was proposed as a royal chaplain by James Hamilton, second marquis of Hamilton [q. v.], but James thought this premature.
Preston's kinsman, Sir Ralph Freeman [q. v.], who had married a relative of George Villiers, first duke of Buckingham [q. v.], now took occasion to represent to Buckingham that he might make friends of the puritans by promoting Preston. Through Buckingham's interest he was made chaplain-in-ordinary to Prince Charles, He took the degree of B.D. in 1620. On Davenant's election (11 June 1621) to the see of Salisbury, Preston had some expectation of succeeding him as Margaret professor of divinity. He felt his Latin to be rusty, and, as an exercise in speaking Latin, he resolved on a visit to the Dutch universities, a project which he carried out with a singular excess of precaution. From the privy council he obtained the necessary license for travel. He gave out that he was going, the next vacation, to visit Sir Richard Sandys in Kent, and possibly to drink the Tunbridge waters. From the Kentish coast he took boat for Rotterdam, in a lay habit with 'scarlet cloake' and 'gold hat band.' In Holland he consorted with Roman catholics as well as protestants. On his return to Cambridge he met the rumour of his having been beyond the seas with a wonder 'at their sillyness, that they would beleeve so unlikely a relation.' After all he had been outwitted, for Williams, the lord keeper, suspecting some puritan plot, had set a spy on his movements, who sent weekly intelligence of his doings.
In February 1622 John Donne (1573-1631) [q. v.] resigned the preachership at Lincoln's Inn, and the benchers elected Preston as his successor. A new chapel, finished soon after his appointment, gave accommodation to the large numbers who flocked to hear him. A more important piece of preferment followed, but it was not obtained without intrigue. Laurence Chaderton [q. v.], the first master of Emmanuel, had held that post with distinction for thirty-eight years. He had outlived his influential friends, and the fellows thought that to secure Preston's interest with Buckingham would be to the advantage of their college. In particular they wanted a modification of the statutes, which enjoined continuous residence, so cutting them off from chaplaincies and lectureships, and at the same time compelled them to vacate at the standing of D.D., whether otherwise provided or not. From Preston's influence they hoped to gain more liberty, as well as to increase the number of college livings. Chaderton thought highly of Preston, but was very reluctant to resign, and doubted whether, if he did, an Arminian might not be appointed. Preston procured a letter from Buckingham (20 Sept. 1622) assuring Chaderton that it was the wish of the king and the prince that he should make way for Preston, and promising him a 'supply of maintenance.' Accordingly
