There is
Roman family name Caesidius which is probably the origin of the Italian given name Cesidio.
For Cesidio several Italian name websites (in Italian) give a meaning of "pale", e.g. this one which also mentions a saint with the name:
http://www.santiebeati.it/nomi/Detailed/1782.html
I have no idea how reliable this information is, however.
Rene www.AboutNames.ch