In search of Sigma cameras history, I encountered interesting fact (sourced from wiki.alquds.edu/?query=Kodak_DCS_Pro_SLR/c) (my emphasis):
The Kodak Professional DCS Pro SLR/c is a 13.5 megapixel digital SLR camera produced by Eastman Kodak. It is full frame—it uses an image sensor that is the full size of a 35 mm (36x24 mm) frame. It is compatible with Canon EOS (EF mount) lenses. The camera was launched on March 18, 2004, and incorporates the internal systems of the previous Nikon-compatible SLR/n in a Sigma SA9 SLR body.