In Ancient Rome, a lex, or law, was not considered valid until it had been inscribed on bronze or stone and deposited in the vaults beneath the temple of Saturn. Space there was limited however, as the temple of Saturn also housed Rome's Treasury, and it is generally accepted that the tablets containing the various leges were actually stored all over the city rather than in the temple proper. Sulla, acting as Dictator of Rome, thus built a repository for the collected laws of Rome, and called it the Tabularium.
Each lex was named after the man or men who produced it and subsequently had it ratified. However the feminine form of their names were used, since lex is feminine gender. This was then followed by a general description of what the law was about.
Leges could be--and many times were--subject to repeal at a later date.