The Spanish soldier Julio Cervera Baviera, who served in the Puerto Rican Campaign, published a pamphlet in which he blamed the natives of that colony for its occupation by the Americans, saying, "I have never seen such a servile, ungrateful country Puerto Rico ... In twenty-four hours, the people of Puerto Rico went from being fervently Spanish to enthusiastically American... They humiliated themselves, giving in to the invader as the slave bows to the powerful lord." He was challenged to a duel by a group of young Puerto Ricans for writing this pamphlet.