General Taylor having successfully invaded Northern Mexico moved the base of active operations to Vera Cruz on the east coast. In January 1847, the 4th Infantry was taken by sea to the port of Vera Cruz and after a siege, the city capitulated. General Scott commanding the Army at Vera Cruz ordered the advance on the capital, Mexico City, in April. On 17 April and 18th General Scott's forces moved through the mountain pass at Gerro Gordo, where General Santa Anna lost his wooden leg in a hasty retreat. The Mexican soldiers fought well and the pass was won only after desperate attacks.