In Ancient Rome, a collegium (plural collegia, "joined by law") was any association with a legal personality. Such associations had various functions.
Collegia could function as guilds, social clubs, or funerary societies; in practice, in ancient Rome, they sometimes became organized bodies of local businessmen and even criminals, who ran the mercantile/criminal activities in a given urban region, or rione. The organization of a collegium was often modeled on that of civic governing bodies, the Senate of Rome being the epitome. The meeting hall was often known as the curia, the same term as that applied to that of the Roman Senate.
By law, only three persons were required to create a legal collegium; the only exception was the college of consuls, which included only the two consuls.
There were four great religious corporations (quattuor amplissima collegia) of Roman priests. They were, in descending order of importance:
The Ancient Greek term for collegium is hetaireia and such organizations existed, from as early as the 6th century BCE in Athens.