Opinions differ on whether he was the same person as Onkelos, who composed the leading Aramaic translation of the Pentateuch, known as Targum Onkelus. The names "Onkelos the proselyte" and "Aquilas the proselyte" are frequently interchanged in the Babylonian Talmud and Jerusalem Talmud.
It is not clear how much (if any) of the Aramaic translation was based on the Greek.
Only fragments of this translation have survived in what remains of fragmentary documents taken from the Books of Kings and the Psalms found in the old Cairo Geniza in Fustat, Egypt, while excerpts taken from the Hexapla written in the glosses of certain manuscripts of the Septuagint were collected earlier and published by Frederick Field in his momentous work, Origenis Hexaplorum quæ Supersunt, Oxford, 1875. Epiphanius' De Ponderibus et Mensuris preserves a tradition that he was a kinsman of the Roman emperor Hadrian, who employed him in rebuilding Jerusalem as Aelia Capitolina, and that Aquila was converted to Christianity but, on being reproved for practicing astrology, 'apostatized' to Judaism. He is said also to have been a disciple of Rabbi Akiva (d. ca. 132 CE). 
In Jewish writings he is referred to as (Aquilas) and ? (Onkelos). Aquila's version is said to have been used in place of the Septuagint in Greek-speaking synagogues. The Christians generally disliked it, alleging that it rendered the Messianic passages incorrectly, but Jerome and Origen speak in its praise.Origen incorporated it in his Hexapla.
The Hexapla were the only known extant fragments of the work until 1897, when fragments of two codices were brought to the Cambridge University Library. These have been published: the fragments containing 1 Kings 20:7-17; 2 Kings 23:12-27 (signed as AqBurkitt) by Francis Crawford Burkitt in 1897, those containing parts of Psalms 90-103 (signed as AqTaylor) by C. Taylor in 1899. A fuller discussion appears in the Jewish Encyclopedia.
The surviving fragments of this translation, and of other Greek translations forming part of Origen's Hexapla, are now being re-published (with additional materials discovered since Field's edition) by an international group of Septuagint scholars. This work is being carried out as The Hexapla Project under the auspices of the International Organization for Septuagint and Cognate Studies, and directed by Peter J. Gentry (Southern Baptist Theological Seminary), Alison G. Salvesen (University of Oxford), and Bas ter Haar Romeny (Leiden University).
The following story about Aquila's conversion appears in Midrash Rabbah:
Once, Aquilas () said to Hadrian the king, 'I wish to convert and to become one of Israel.' He answered him, 'You are seeking [to join] that nation? How have I despised it! How have I killed it; the most downtrodden of the nations you are asking to join!? What have you seen in them that you wish to be made a proselyte?' He replied, 'The smallest of them knows how the Holy One, blessed be He, created the universe; what was created on the first day and what was created on the second day, and how many [years] have passed since the universe was created, and by what [things] the world is sustained. Moreover, their Divine Law is the truth.' He said to him, 'Go and study their Divine Law, but do not be circumcised.' Aquilas then said to him, 'Even the wisest man in your kingdom, and an elder who is aged one-hundred, cannot study their Divine Law if he is not circumcised, for thus is it written: "He makes known his words to Jacob, his precepts and judgments to Israel. He has not done the like of which to any other nation." Unto whom, then, [has he done it]? Unto the sons of Israel!'
This article incorporates text from a publication now in the public domain: Singer, Isidore; et al., eds. (1901-1906). The Jewish Encyclopedia. New York: Funk & Wagnalls. Missing or empty