Onkelos the Convert אונקלוס הגר

Megillah 3a says: the Targum of the Torah was composed by Onkelos the convert from the mouths of Rabbi Eliezer and Rabbi Joshua. That is, the translation was not private work: it was made under the supervision of two heads of the generation, and so acquired a standing no other translation has.

Nor is it a translation in the modern sense. Where the text speaks of God in bodily terms — "hand," "eyes," "came down" — Onkelos renders it obliquely; where a verse is difficult, he chooses one of the possible readings and thereby interprets. He is therefore read as a commentary, and Rashi consults him constantly.

The law requires going through the weekly portion shenayim mikra ve-echad targum — twice the text and once the translation — and the translation meant is his.

Gittin 56b tells of his origins: Onkelos bar Kalonikos was the son of Titus's sister. The Gemara there relates how he raised spirits to ask whom he should join — and became a Jew regardless.