Labelled by the European Catholic Church as heretics in the 5th century, they founded Church of the East and Syriac Church in the 1st century AD (erroneously renamed Nestorian and Jacobite by Western Christians). They have kept alive one of the oldest Christian liturgies; they translated ancient Greek texts first into Syriac and vice versa, and then into Arabic, and evangelised China, India and Mongolia during the Golden Age of the Arabic Empire.