Complex sentence: Global regulation of opium began with the stigmatization of Chinese immigrants and opium dens in San Francisco, California, leading rapidly from town ordinances in the 1870s to the formation of the International Opium Commission in 1909.
Split into simpler sentences: Global regulation of opium began with the stigmatization of Chinese immigrants and opium dens in San Francisco, California. This led rapidly to town ordinances in the 1870s and the formation of the International Opium Commission in 1909.