Eliya I of Seleucia-Ctesiphon

Eliya I was Patriarch of the Church of the East from 1028 to 1049. He is also known as the author of an early grammar of Syriac written around the year 1000.

Eliya's patriarchate
The following account of Eliya's patriarchate is given by Bar Hebraeus:

He [Ishoʿyahb IV] was succeeded by Eliya I, formerly bishop of Tirhan, a man of advanced age and a learned doctor. He introduced the rite of genuflection on the holy Sunday of Pentecost, which the Nestorians previously did not observe. At the end of his life he was afflicted by a paralysis of his limbs and was confined to bed. He was consecrated on the third Sunday of the Apostles, on the seventh day of the third month of the Arabs in the year 419 [AD 1028/9] in the Greek Palace in Baghdad. His election was conducted by the drawing of lots. He died after fulfilling his office for twenty-one years, and was buried in the Greek Palace on the Sunday after Ascension, on the seventh day of iyyar [May] in the year 440 of the Arabs [AD 1048/9].

His secretary was the famous polymath Ibn al-Tayyib.