The monastery that St Botolph established at Icanhoh in AD 654 was destroyed by Viking invaders in the winter of AD 869-70. The church erected on its site was damaged by fire in 1968 and in 1977 a stone was observed built into one of the partly ruined walls. It turned out to be the shaft of a stone cross of the 9th or early 10th century which had probably been erected in memory of the saint and his monastery.
The cross shaft can be seen in Iken church: http://www.achurchnearyou.com/iken-st-botolph/
West S.E., Scarfe, N. and Cramp, R., ‘Iken, St Botolph, and the coming of East Anglian Christianity’, Proceedings of the Suffolk Institute of Archaeology and History vol. XXXV pt 4, 1984, 279-301.