Matthew Poole and continuators on Acts 6:9

9 ¶ Then there arose certain of the synagogue, which is called the synagogue of the Libertines, and Cyrenians, and Alexandrians, and of them of Cilicia, and of Asia, disputing with Stephen.

Synagogues were as Colledges in our Universities, being used for Instruction and Learning; and were distinguished according to the persons that frequented them.

Some think, these were natives of a certain Countrey in Africa, from whence they were so called; but more probably, they were such as were manumitted or made free, (as the word is commonly used for such) and in a middle condition between such as were free-born, and such as were bond-slaves; and might desire to frequent with those of their own rank.

The Iews spake of no less than 480. Synagogues at Ierusalem, a vast number, and probably increased by them, tho several places are called Cyrene; this (from whence they took their name) was in Africa in all likelihood, it being joyned with that of the Alexandrians: So God pleased to sever the Hellenists, (or Iews by traduction) for the Gentiles were not yet called; that they might all hear the Gospel in the Language they understood best.