Argive Reckoning, or AR for short, is the calendar used in Magic: The Gathering. It sets year 0 as the year in which both Urza and Mishra were born. It only came into use many years after the time of the Brothers, and was used informally for several thousand years before an attempt was made to clarify historical facts. It is named after New Argive, a country famed for its scholars. The latest time the date was mentioned, or could be directly derived from the storyline, was the year 4306 AR.

= Alternate Calendars =

At the time of The Brothers, the most commonly used calendar system was Penregon Founding (PF), which set its year 0 as the year Penregon, Capital of Old Argive, was founded. When Urza and Mishra were born, the year was 912 PF.