According to wikipedia:
"The M1911 pistol originated in the late 1890s search for a suitable self-loading (or semi-automatic) handgun to replace the variety of revolvers then in service."
At least 2 revolvers are mentioned in the article, one in 38 Long Colt which appears to have been the 1889 that USMA-82 points out, and another in .45 Colt which appears to have been the venerable Colt Single Action Army.