Complex sentence: The first stockmen's association in Montana was formed in Virginia City in 1873 to discuss branding standards, how to deal with rustling and how to influence the territorial legislature to pass laws favorable to the cattle industry.
Split into simpler sentences: The first stockmen's association in Montana was formed in Virginia City in 1873. The association was established to discuss branding standards, how to deal with rustling and how to influence the territorial legislature to pass laws favorable to the cattle industry.