Every document which has a Cuthean witness on it is void, except for gittin and [documents of] emancipation of slaves. It once occurred that they brought before Rabban Gamliel in Kefar Usnai a get whose witnesses were Cutheans, and he validated [it].  All documents which are processed in gentile courts, although their signatories are gentiles, are valid, except for gittin and [documents of] emancipation of slaves. R' Shimon says: These are also valid; they were not mentioned [as being void], except when they were made by private individuals.