After 1551, the Reformation advanced further, with the approval and encouragement of Edward, who began to exert more personal influence in his role as Supreme Head of the church. The new changes were also a response to criticism from such reformers as John Hooper, Bishop of Gloucester, and the Scot John Knox, who was employed as a minister in Newcastle upon Tyne under the Duke of Northumberland and whose preaching at court prompted the king to oppose kneeling at communion. Cranmer was also influenced by the views of the continental reformer Martin Bucer, who died in England in 1551, by Peter Martyr, who was teaching at Oxford, and by other foreign Theologians. The progress of the Reformation was further speeded by the consecration of more reformers as bishops. In the winter of 1551–52, Cranmer rewrote the Book of Common Prayer in less ambiguous reformist terms, revised canon law, and prepared a doctrinal statement, the Forty-two Articles, to clarify the practice of the reformed religion, particularly in the divisive matter of the communion Service. Cranmer's formulation of the reformed religion, finally divesting the communion Service of any notion of the real presence of God in the bread and the wine, effectively abolished the mass. According to Elton, the publication of Cranmer's revised prayer book in 1552, supported by a second Act of Uniformity, "marked the arrival of the English Church at Protestantism". The prayer book of 1552 remains the foundation of the Church of England's services. However, Cranmer was unable to implement all these reforms once it became clear in spring 1553 that King Edward, upon whom the whole Reformation in England depended, was dying.