On May 21, 1898, the Great Northern War started with a bang when a Russian regiment crossed the border from Alaska into California and began driving south towards San Francisco. It is unknown to what extent this was due to Russian concerns about Mexican military maneuvers, and to what extent it was the result of manipulation by Kramer Associates President Diego Cortez y Catalán. Sobel notes that most accounts indicate that the first attack came from the California side, but that it is "impossible to be certain."
On May 21, 1920, President Emiliano Calles signed the Manumission Act into law, setting a process in motion that would phase out slavery in Mexico over the course of the next year. Calles' Secretary of State, Albert Ullman, called the Act's passage "the removal of a stain, long overdue."