He studied with the Dominican friars in Mosul and later in the College of the Propaganda in Rome and was ordained priest in April 1873.

After the death of Ignatius Behnam II Benni (13 September 1897) he was elected Patriarch on 9 October 1898 and confirmed by Pope Leo XIII on 28 November 1898.

The arrival of World War I was catastrophic: the Armenian genocide brought destruction also to the Christian Syrians who lived in the same areas as the Armenians, with the result that the Syriac Catholic Church had the number of its members cut by half[6] with five dioceses (of ten) and fifteen missions destroyed.

[7] Ephrem Rahmani was a liturgical scholar of international repute.

[4] In 1899 he discovered and published the first edition of the 4th-century text Testamentum Domini.