Complex sentence: From here, the regiment carried out the historic reconnaissance of the Black Hills in 1874, making the discovery of gold in the Black Hills public and starting a gold rush that precipitated the Great Sioux War of 1876--77.
Split into simpler sentences: From here, the regiment carried out the historic reconnaissance of the Black Hills in 1874. This led to making the discovery of gold in the Black Hills public and starting a gold rush that precipitated the Great Sioux War of 1876--77.