大秦景教流行中国碑
For Christians in Persia, the change from Zoroastrian to Islamic rulers did not worsen their situation, but rather bettered it, especially for the "Nestorians" (East Syrians). This was a time of increased missionary activity by the Church of the East, whose success in China with the missionary Alopen is attested by the Nestorian Stele and in India by the continued maintenance of its liturgy by the Syro-Malabar Church. The patriarchate of Timothy I (780–823) was a high point of the Church's expansion.