He joined the Benedictines at Norwich moving on to the Benedictine Gloucester College, Oxford where he became one of the most outstanding students of his generation, being especially proficient in Hebrew. He is known to have accompanied Simon Langham to Rome, then Montefiascone and Avignon and he held the post of socius in Langham's household. Being a man of learning and ability, he obtained a post in the Curia.
He was instrumental in the attack and subsequent condemnation of John Wycliff and supporting Catholic orthodoxy in England. He was made a Cardinal by Urban VI, on 21 September 1381. On 7 March 1381 or 1382, he was nominated Dean of York. He arranged Richard II and Anne of Bohemia's wedding coronation in the Abbey and probably composed the Liber Regalis. A document in the Abbey concerning the coronation offerings gives him as Cardinal of Santa Cecilia in Trastevere. In 1385 he was imprisoned at Nocera in Campania by Urban on a charge of conspiring with five other cardinals against the pope and was deprived of his cardinalate and deanery. With his fellow captives he was dragged across Italy arriving at Genoa in autumn 1385. Here the others were put to death but Adam was spared through the personal intervention of Richard II.
The next pope, Boniface IX, restored his cardinalate 18 December 1389. It has been suggested that for a time Easton returned to England. The Norwich Record Office documents the sending of the Cardinal's books by way of the Low Countries to Norwich for his use there. He retained benefices in England throughout this period, including Somersham, the deanery of York and a prebend in Salisbury Cathedral, which he subsequently exchanged for the living of Heygham (Heigham) in Norfolk.
He wrote many works the most significant of which was a massive volume entitled the Defence of Ecclesiastical Power, supporting the position of the Catholic Church and damning Wyclif's theology as false and erroneous. This and a number of his other works still exist, as do some of the manuscripts of his library, which were shipped back to Norwich from Rome in six barrels, and he composed the Office for the Visitation of Our Lady. He effected the canonization of Birgitta of Sweden in 1391 with a structured attack on a Perugian 'Devil's Advocate', a document in which he defended women's visionary writings.
He may have been Julian of Norwich's spiritual director, editing her Long Text Showing of Love in the same way that Birgitta of Sweden's spiritual director, Alfonso of Jaen, edited her Revelationes. Alfonso became director to Catherine of Siena, whose confessor and executor was William Flete, the Cambridge-educated Augustinian Hermit of Lecceto, and to Chiara Gambacorta. Easton's Defense of St Birgitta echoes Alfonso of Jaen's Epistola Solitarii, and William Flete's Remedies against Temptations, all of which appear in Julian's text.
He died at Rome, 15 September (according to others, 20 October) 1397. His tomb, constructed later, is in his Cardinalate Basilica of Santa Cecilia in Trastevere.
- Andrew Lee (2006), The Most Ungrateful Englishman, The Life and Times of Adam Easton
- Julia Bolton Holloway (2006), Anchoress and Cardinal: Julian of Norwich and Adam Easton, O.S.B.