In 1402 a ship belonging to Fenn, the Michael, was seized off Plymouth by a vessel from Rostock, one of a number of incidents taken up by the government of Henry IV with the Hanseatic League.
[2] On 22 March 1406 a ship of which he owned one-third was off Flamborough Head when it seized the Maryenknyght from Danzig, sailing out of Leith with a cargo of wool and leather.
On board was the 11 year old Prince James, heir to the throne of Scotland, who had been sent to France by his father King Robert III under the care of the Earl of Orkney.
King Henry IV made a prisoner of the unfortunate young prince, who was treated well but not released until 1424,[3] and rewarded Fenn and his co-owners with not only all the cargo of the Hanse vessel but also the privilege of shipping goods out of Yarmouth free of all customs duties to wherever they liked.
The will, proved in Norwich on 25 February 1409, divided his assets between his three surviving sons, with his wife Christine keeping an interest for life in a substantial portion.