In ancient Rome, the principle of private association was recognized very early by the state. Sodalitates for religious purposes are mentioned in the XII Tables, and collegia opificum, or trade guilds, were believed to have been instituted by Numa Pompilius, which probably means that they were regulated by the jus divinum as being associated with particular cults. It can be difficult to distinguish between the two words collegium and sodalitas. Collegium is the wider of the two in meaning, and may be used for associations of all kinds, public and private, while sodalitas is more especially a union for the purpose of maintaining a cult. Both words indicate the permanence of the object undertaken by the association, while a societas is a temporary combination without strictly permanent duties.