1.Existence of ~130 (120 syrian,10 latin ) christian churches at the time of
Synod of Udayamperoor.
2.Sizable population of non catholic churches like Orthodox,Jacobite,Marthoma ( who do not indulge in evangelism /7 has no connection with Catholic church or Portuguese)
then there are historical references-
Pinne iniyum Confusion aakaruthu,Nasrani=Syrian Christian-Members of Syro Malabar,Orthodox,Jacobite,Marthoma,Syro Malankara & Chaldean Church in Kerala.
Those converted by Portuguese (Latin) & by British CMS (CSI) doesnt count.