An Anglo-Russian force of 32,000 men landed in North Holland on August 27, 1799, captured the Dutch fleet at Den Helder on August 30 and the city of Alkmaar on October 3. Following a series of battles at Bergen on September 19 and Alkmaar on October 2 (also known as 2nd Bergen), they faced the French and Dutch armies at Castricum on October 6. Following a defeat at Castricum, the Duke of York, the British supreme commander, decided upon a strategic retreat to the original bridgehead in the extreme north of the peninsula. Subsequently, an agreement was negotiated with the supreme commander of the Franco-Batavian forces, General Guillaume Marie Anne Brune, that allowed the Anglo-Russian forces to evacuate this bridgehead unmolested. However, the expedition partly succeeded in its first objective, capturing a significant proportion of the Batavian fleet.