5000 Pesos Pattern, 50th Anniversary of Nationalization of Oil Industry, Bimetallic

This piece was struck to mark the fiftieth anniversary of President Lázaro Cárdenas's March 18, 1938 expropriation decree, which nationalized foreign oil holdings — primarily British and American — and created Pemex. The political shock was considerable: Britain severed diplomatic relations with Mexico entirely, and the U.S. applied sustained economic pressure. Mexico paid off the expropriation debt in installments that ran until 1962.

As a pattern, it never entered circulation. The bimetallic construction anticipates the format Mexico would later adopt for its circulating coinage in the early 1990s.