In 1625, the Spanish army was 230,000 regulars (80,000 in field armies, 150,000 in garrisons), exclusive of naval personnel and militia. The regular Spanish army grew in size from around 20,000 in the 1470s, to around 300,000 by the 1630s during the Thirty Years' War that tore Europe apart, requiring the recruitment of soldiers from across Europe. With such numbers involved, Spain had trouble funding the war efforts on so many fronts. The non-payment of troops led to many mutinies and events such as the Sack of Antwerp (1576), when unpaid tercio units looted the Dutch city. Spain's holdings in Italy and the Low Countries contributed large amounts of men and treasure to the empire's army: each province was allotted a number of troops it had to pay for (including the ethnic Spanish garrisons) and recruits it had to provide. Troops were generally sent outside of the areas they were recruited in. From 1635 to 1659, the Duchy of Milan provided 100,000 soldiers to the Spanish army, while the Kingdom of Naples provided 53,500 (plus a naval expedition) from 1631 to 1636 alone.