mercedinus

Updated: May 9, 2025

Numa reckoned the variation to consist of eleven days, as the lunar year contains three hundred and fifty-four days, and the solar year three hundred and sixty-five. He doubled these eleven days and introduced them every other year, after February, as an intercalary month, twenty-two days in duration, which was called by the Romans Mercedinus.

Plutarch - Plutarch's Lives, Volume I

Numa, calculating the difference between the lunar and the solar' year at eleven days, for that the moon completed her anniversary course in three hundred and fifty-four days, and the sun in three hundred and sixty- five, to remedy this incongruity doubled the eleven days, and every other year added an intercalary month, to follow February, consisting of twenty-two days, and called by the Romans the month Mercedinus.

Plutarch - Plutarch: Lives of the noble Grecians and Romans