Immediately after returning to Paris, Betances became a key contact for the Cuban insurgency in Paris. He made several fund raising efforts, including one that attempted to fund quinine shipments to the Cuban rebels, to ease their pain when infected by malaria in the island battlefields. These efforts outlasted the Pact of Zanjón, which ended the Ten Years' War in 1878. Betances also used his diplomatic contacts to guarantee humane treatment (and eventually freedom from imprisonment) to José Maceo, the brother of Antonio Maceo, the later military leader of the Cuban War of Independence, when both Antonio and José were arrested by the Spanish government in 1882. The Maceo brothers both escaped imprisonment, were recaptured in Gibraltar and turned over to the Spanish authorities, but José remained in jail long after Antonio regained his liberty and fled to New York City. Betances even used Lord Gladstone as a mediator, and attempted to convince him of having Jamaica (where his family had properties) join an Antillean Federation.