Like Spearhafoc, Mannig's biography, with some precise details, is given in the chronicle maintained by his abbey. His work also had a miracle associated with it – the lay goldsmith Godric stabbed his hand with an awl during the work on the large shrine at Evesham, which was miraculously healed overnight. Spearhafoc and Mannig are the "only two goldsmiths of whom we have extended accounts", and the additional information given about Godric, the leader of a team brought in by Mannig for the shrine, is also unique among the surviving evidence. Some twenty years after the miracle, Godric joined the Abbey of Evesham, presumably in retirement, and his son later became Prior there.