In pre-modern sources, Assyrians (Atorāye) were inhabitants of the area or ecclesiastical province of Ator, around Mosul. In modern times, however, the name has taken on two expanded senses: to denote 1. the whole ethnic group historically represented by the Ch. of E.; and sometimes 2. the supposed ethnic group represented by all the Syriac churches.

1. In medieval sources there are isolated references that connect Syr. Christians with the ancient Assyrians, but this identification was not developed until the 19th  cent. A. H. Layard identified the Christians he met as descendants of the ancient Assyrians whose buildings he was excavating (Nineveh and its Remains, vol. 2 [1848], 237). Since the area around Mosul had been called ‘Assyria’ from ancient times, this identification was not unnatural. It was a further development, however, when Anglicans (probably first G. P. Badger), seeking to avoid the word ‘Nestorian’, began to use the name ‘Assyrian Christians’ for the whole Church of the East. This usage was made official by the Archbishop of Canterbury’s Mission to the Assyrian Christians (1886) — although the missionaries did not use the word once they were in the field. The general adoption of ‘Assyrian’ and the Assyrian ethnology by the people themselves came after 1900 under the influence of nationalist writers like Freydon Atoraya. It was further encouraged when the founding of the present state of Syria made it more urgent to find an ethnic name other than ‘Syrian’. A  popular etymology had it that Surāyā (a variant of Suryāyā, ‘Syrian’) was a corruption of Asurāyā (even though correctly ‘Assyrian’ is Atorāyā). Whatever its background, the name ‘Assyrian’ has proved convenient and is now generally used even by those who do not accept the connection with ancient Assyria. The Church of the East, although it has not especially promoted this connection, is officially styled ‘Church of the East of the Assyrians’ or ‘Assyrian Church of the East’. Among Chaldean Catholics, ‘Assyrian’ has had to compete with ‘Chaldean’ as the preferred ethnic name. Some have adopted ‘Assyro-Chaldean’ as a compromise.

2. The name ‘Assyrian’ was already in use in some W.-Syr. circles before World War I. It was popularized in the USA by writers like Naʿʿūm Fāʾiq, and D. B. Perley who insisted that the different Syriac churches, eastern and western, were accidental divisions within a single nation. (From this period dates the adoption of ‘Assyrian’ into the names of some American Syr. Orth. parishes, who retain it today although without the accompanying nationalist agenda.) The Syr. Orth. hierarchy has generally opposed the name ‘Assyrian’, and writers within the Church emphasize its Aramean heritage over against any alleged Assyrian one.