 On 17 March 1640, three Portuguese ships under the command of Rodrigo Lobo da Silva, ran aground in the Bocagrande Channel.This accelerated the formation of a sand bar, which soon connected the Bocagrande Peninsula to the island of Tierrabomba.The defense of the bay then shifted to two forts on either side of Bocachica, "San Jose" and "San Luis de Bocachica".