Nestorian and Orthodox Christianity came to China centuries before Roman Catholicism and motley Protestant sects, yet they have no legal standing in China at all. 

Whereas some Protestant and Catholic ("Chinese Catholic" as opposed to Roman-Catholic) churches have been returned, no Orthodox churches have been (even though there are Russians as one of the 54 recognised nationalities of China -- a small number of them, but nonetheless). 

Judaism was present in China for a very long time too and is tolerated today, but not officially recognised either.