Osiel Cárdenas Guillén was the leader of the syndicate that was part of what country?
Osiel Cárdenas Guillén Osiel Cárdenas Guillén (born May 18, 1967) is a former Mexican drug lord and the former leader of the Gulf Cartel (Spanish: "Cártel del Golfo" ) and Los Zetas. Originally a mechanic in Matamoros, Tamaulipas, where he was born, he entered the Gulf Cartel by helping Juan García Abrego, the capo at the time; when García Ábrego was arrested in 1996, some infighting erupted within the cartel. Osiel Cárdenas eventually took control by killing his friend and contender Salvador Gómez, earning Cárdenas the nickname ""El Mata Amigos"" (The Friend-Killer).
Treaty of Pilar The Treaty of Pilar (in Spanish, "Tratado del Pilar") was a pact signed among the rulers of the Argentine provinces of Santa Fe, Entre Ríos and Buenos Aires, which is recognized as the foundation of the federal organization of the country. It was signed in the city of Pilar, Buenos Aires on 23 February 1820 by governor Estanislao López for Santa Fe, "caudillo" Francisco Ramírez for Entre Ríos, and provisional governor Manuel de Sarratea for Buenos Aires, after the dissolution of the national government caused by the Battle of Cepeda. A reference to it was included in the Preamble of the Argentine Constitution of 1853 as one of the "pre-existing pacts" fulfilled by it.