By May, Frederick was on the move, his army slowed by drunken brawls between soldiers from different regions of the Empire and by the need to recapture other cities from the Burgundians. But by the end of May he had arrived, and the Burgundians, after signing a provisional treaty, began to dismantle their siege works. At first, Burgundians, Imperials, and Kölners fraternized, but soon the Germans began to harass the Burgundians (the Kölners stole five Burgundian ships loaded with cannon), precipitating a sudden and violent assault on the unsuspecting Germans. Sporadic fighting continued until the papal legate present at the siege threatened to excommunicate both Charles and Frederick unless they ended the fighting; this threat, probably an idle one, enabled the two monarchs to conclude hostilities without losing face. The siege was finally terminated on 27 June 1475.