Zoca was originally a small bastion between the two larger Orange and King's Bastions. This had been the site of a fortification since Gibraltar's Moorish period when there was a tower here on the old Moorish city wall. In 1627 when Gibraltar was under Spanish control, the tower was reduced and by the time of the Great Siege (1779-1783) it had become a broad platform incorporating an artillery battery. Its Spanish-era appearance is shown in a 1627 drawing by Luis Bravo de Acuna, and John Drinkwater depicts its rebuilt form in his contemporary account of the Great Siege.