The Blackfriars Bridge Hoard was a dispersed hoard recovered from the Thames foreshore in London near the northern foot of Blackfriars Bridge in the mid 1990's. Roughly 1,582 coins were recovered, mainly silver shillings and halfcrowns of Charles I and the Commonwealth, the earliest coin in the hoard was typically a fine silver issue of Edward VI. The total face value of the hoard at the time of deposit was ₤92 14s.The latest coins were  dated 1660 and it would seem most likely that the hoard was deposited in 1660, the year of Charles II restoration and the end of the Commonwealth periods experiment in republican government. At the time of the hoards loss the present foreshore was out in the open channel of the river. The 1870 completion of the Thames Embankment in this area narrowed the river and extended out the bank. The hoard would have therefore been lost in open water and one can speculate that it was perhaps dropped whilst being moved aboard ship or perhaps entered the water from a capsized row boat. One could further speculate that the money belonged to a person attempting to leave London and England in haste. A person closely associated with the republican regime would have had good cause to do this in 1660 as the political tide turned towards the restoration of the monarchy. It was perhaps in this period and under these circumstances that a chest or bag of coins were lost in the waters of the Thames by a person fearing the vengeance of a returning king and his followers.

References:

Baldwin's Auctions, #14, 13-14 October 1997, pp.29-42 (Hoard sold at auction)

Hazel Forsyth and B. J. Cook, "New Hoards from Seventeenth-Century England, Blackfriars Bridge, London", BNJ 69, p.p. 157-167.