Archdiocese of Goa in the context of "Synod of Diamper"

The Synod of Diamper (Udayamperoor Synod) (Malayalam: ഉദയംപേരൂർ സൂനഹദോസ്, romanized: Udayampērūṟ Sūnahadōs), held at Udayamperoor (known as Diamper in non-vernacular sources) in June 1599, was a diocesan synod, or council, that created rules and regulations for the ancient Saint Thomas Christians (also known as Mar Thoma Nasranis) of the Malabar Coast, a part of modern-day Kerala state, India, formally subjugating them and downgrading their whole Metropolitanate of India as the Diocese of Angamale, a suffragan see to the Archdiocese of Goa administered by Latin Church Padroado missionaries. This synod also introduced forced Liturgical Latinisation and the eschewal of local practices and beliefs, leading to a significant ecclesial protest by Saint Thomas Christians known as Coonan Cross Oath and a subsequent schism in the mid-17th century.