Pier's army was mainly active against the Dutch and the Burgundians. This was why he formed an alliance with Karel van Gelre (1492-1538) who at the time was trying to regain his Duchy from Filip the handsome (Filip de Schone, 1479-1506). On land the Anglo-Saxon hirelings were too powerfull for Pier's army, but on water Pier was unbeatable. Like true pirates his "army" entered any ship of the enemy. An entire fleet of eleven Anglo-Saxon ships was beaten and their ships captured.
A Dutch fleet of ships of war was also beaten in 1515 in the southern
sea. Twentyeight ships were captured and only eight ships escaped. At that time
he was given the nickname: the Cross of the Dutchmen (Het Kruis der Hollanders).
In between his fights with the enemy he also captured several merchant ships.
Most of these he fitted out for battle. Pier's fleet consisted of so-called
'Signal ships', small manoeuverable ships of about 30 men, that operated from
the harbours in Workum and Makkum. In 1517 he used these Signal ships to attack
Medemblik. After plundering Texel, Wieringen and Emmerink Pier retired in 1519.
He died in Sneek in the year 1520 on October 28th.