English Benedictine monk, historian, apologist, and spiritual writer noted for his editorship of writings by Counter-Reformation mystics.

Educated at Merton College, Oxford, Cressy became chaplain to Sir Thomas Wentworth (later earl of Strafford) and subsequently to Lucius Cary (later Lord Falkland); he was also dean of Leighlin, County Carlow, and canon of Windsor, Berkshire. While in Rome (1646), he converted to Roman Catholicism—owing to the writings of Father Augustine Baker (Baker, Augustine) and to Cary's death in the English Civil Wars (1643)—and became a monk of St. Gregory's, Douai (1649). Returning to England after the Restoration of Charles II in 1660, he was appointed chaplain to Queen Catherine of Braganza at Somerset House.

His Exomologesis, an account of his conversion, appeared in Paris in 1647; he also wrote Church-History of Brittany or England, from the Beginning of Christianity to the Norman Conquest (1668) and several controversial tracts. His chief significance is as editor of the mystics Walter Hilton (1659), Blessed Julian of Norwich (1670), and Maurice Chauncey.