Complex sentence: Historically, racial and ethnic classification has been closely related with Mexico's society, however since the end of the Mexican Revolution, the official identity promoted by the government has been the Mestizo one (a mix of European and indigenous culture and heritage).
Split into simpler sentences: Historically, racial and ethnic classification has been closely related with Mexico's society. However, since the end of the Mexican Revolution, the official identity promoted by the government has been the Mestizo one (a mix of European and indigenous culture and heritage).