The Silurian was named in 1835 by Roderick Murchison, who took the name from the Silures, an ancient Celtic tribe of south Wales. The Silures began fighting the invading Romans about 48 AD. Their guerilla war was successful for something like 30 years, and it wasn’t until about 78 AD that the Silures were incorporated into Roman Britain. It’s not clear whether they eventually just acquiesced or were conquered in a military campaign.
The oldest sedimentary rocks of Britain, called the Primitive Series, were subdivided into the Cambrian and Silurian by Adam Sedgwick and Roderick Murchison, respectively. We talked in late February about the controversy those two friends became embroiled in over which rocks were in which period, a 40-year-long argument that was finally settled by the establishment of the Ordovician Period, also named for a Welsh tribe.
—Richard I. Gibson
Map from Wikipedia, used under GNU free documentation license.