Library. William was educated at the great West Country college of Exeter, at Oxford, arriving there in 1520 when he was about 14 (the usual age at that time), from whence he was elected Fellow of All Souls in 1523 where he graduated Bachelor of Civil and Canon Law on 2 July 1526 (both colleges were generously endowed by him later). Proficient both in Roman (administrative) and ecclesiastical law, in about 1527, he became Principal of Peckwater's Inn or Vine Hall, and tutor to George Boleyn (son of the Earl of Wiltshire and afterwards Viscount Rochford). It was no doubt through the influence of Boleyn's sister Anne that Petre came to the notice of Thomas Cromwell (she sent him presents, and promised him any pleasure it was in her power to give) and was introduced at court and selected for government service. He was sent abroad and resided on the continent, chiefly in France, for more than four years. On his return, he was appointed a Clerk in Chancery and All Souls made him Doctor of Civil Law on 17 February 1532. In 1534, William and Edmund Walsingham examined Anne Husee on the charge of addressing Henry's daughter Mary as Princess when Anne had stayed with her at Hunsdon, and whether she thought her the lawful daughter of the king. Anne Husee, knowing her head to be in danger if she continued to support Mary, took the more prudent way and besought pardon. 'She most humbly beseecheth his Highness of mercy and forgiveness, as One that is repentant for that she hath so offended and purposeth never hereafter to fall in to semblable danger, – signed Anne Husee, countersigned Edmund Walsyngham. Per me Gulielmum Petre'. He was only about thirty when he was already in high favour with Cranmer and Cromwell, who spoke in November 1535 of making Petre dean of arches, there 'being no man more fit for it'. On 13 January 1536, he was appointed deputy or proctor for Cromwell in his capacity as Vicar-General and appointed Visitor of the greater monasteries in Kent and other southern counties, being especially active in the West Country. In the same year, he was made Master in Chancery, was placed on a commission to receive and examine all bulls and briefs from Rome, and granted the prebend of Langford Ecclesia in Lincoln Cathedral, which he resigned the following year. On 16