The sixteenth-century Acts and Monuments by John Foxe was more than a martyrology, which memorialised the persecutions of Mary I's reign. It was also an ecclesiastical history which saw the Christian past as a battle between the church of Christ and the church of Antichrist. This thesis identifies the sources that Foxe and his collaborators used to compile the pre-reformation account in the first two editions of the Acts and Monuments (1563 and 1570 respectively). Foxe was producing a revisionist history that saw the past as revelation of prophecy and Scripture. So many of his sources - chronicles and annals written by monks and clergy - were suspected witnesses, no longer considered truthful or accurate. Foxe needed to sift through these texts to find `God's truth' as he understood it, and to rehabilitate certain authorities over others. Central to this thesis is the contention that Foxe did not do this alone. He worked as part of an extended network of scholars, printers, and reformers. His predecessor and mentor, John Bale was a vital foundation for his research; the German ecclesiastical history usually entitled the Magdeburg Centuries was an enormous influence; and the `circle' of scholars focused around Archbishop Matthew Parker, proved to be an invaluable source for rare or hard to find chronicles and annals. This study of Foxe's pre-reformation sources helps us to understand this collaborative context and to explore how he came to conceptualise the past and to redefine the interpretation of events and historical characters. It will, in particular, focus upon the significance of Foxe's pioneering role in the survival and transmission of manuscript materials relating especially to the English medieval and Anglo-Saxon past.