James' Catholic deputy, the Earl of Tyrconnell, had raised an Army of around 36,000, although many were poorly equipped and it was almost impossible to feed, pay and supply so many. Although they quickly occupied much of Ireland, including largely Protestant Ulster, they were unable to capture the key northern port of Derry and were forced to retreat at the end of July. In August, Williamite general Schomberg landed in Belfast Lough with 15,000 reinforcements, but logistics failures meant his army stalled at Dundalk and suffered heavily from sickness and desertion.