Charles Xavier Thomas de Colmar (May 5, 1785–March 12, 1870) was a French inventor and entrepreneur best known for designing, patenting and manufacturing the first commercially successful mechanical calculator, the Arithmometer, and for founding the insurance companies Le Soleil and L'aigle which, under his leadership, became the number one insurance group in France at the beginning of the Second Empire. After a short employment in the French administration, he joined the French army in 1809 eventually reaching the level of General Manager of the supply store of all of the armies located in Spain in 1813. Shortly thereafter he was promoted to Inspector of Supply for the entire French army. It was during that time that he conceived the idea of the Arithmometer to help him with the great deal of calculations that he had to perform.