Captain Ruth Maximiliaan started the Second Anglo-Dutch War in command of a Lisbon trader Catherina (about 40 guns). At the action at Bergen, when an English squadron attempted to attack Pieter de Bitter's Retourvloot, Ruth Maximiliaan's ship was in a tight spot, in line between the Walcheren and Slot Hooningen. The harbor mouth was so narrow that there was only room for 7 ships, including the Catherina. In the fierce battle, the Catherina was holed underwater and had to be run ashore to keep from sinking. At the Four Days Battle, where he commanded the Rotterdam warship Wassenaer (56 guns), Ruth Maximiliaan took part in the fight with John Harman's ship Henry. The Dutch were convinced that she must have been sunk, although the Henry survived to fight another day. On the second day of the battle Captain Maximiliaan played a major part in sinking the Black Eagle (the former Friesland ship Groningen). Ruth Maximiliaan was killed at the St. James's Day Battle from 4-5 August 1666 (July 25-July 26 Old Style). Frank Fox called him one of De Ruyter's best captains.