 Complete the following phrase:  After Mexicos independence in 1821, a large body of Spanish troops continued to occupy San Juan de Ulúa as late as 1825. It was the last site in the former colony of New Spain to be held by the Spanish and was surrendered to Mexican General Miguel Barragán in November 1825. The justification for the order of expulsion issued by President Vicente Guerrero was their failed attempt at re-conquering Mexico. Since then, San Juan de Ulúa served as a military and political symbol of Mexican resistance to foreign invasions and occupations, thanks to several of which took place during the nineteenth century. In 1836 the French bombarded the fortress in the 