In 1645, Garcia II sent a force against Daniel da Silva under the command of his son, Afonso. The campaign was a failure, due to Kongo's inability to take Soyo's fortified position at Mfinda Ngula. Worse still, Afonso was captured in the battle, forcing Garcia to engage in humiliating negotiations with da Silva to win back his son's freedom. Italian Capuchin missionaries who had just arrived in Soyo, in the aftermath of the battle, assisted in the negotiations. In 1646, Garcia sent a second military force against Soyo, but his forces were again defeated. Because Garcia was so intent on subduing Soyo, he was unable to make a full military effort to assist the Dutch in their war against Portugal.