Kalends Medieval Date Parser
Convert a Roman-style medieval date ('ante diem n kalends/nones/ides of month M') into a day of month by exact inclusive backward counting, with the Ides on the 15th of March/May/July/October and the Nones eight days earlier; leap-year Februaries use the 29-day mapping (medieval scribal practice around the bissextile varied).
Description
Convert a Roman-style medieval date ('ante diem n kalends/nones/ides of month M') into a day of month by exact inclusive backward counting, with the Ides on the 15th of March/May/July/October and the Nones eight days earlier; leap-year Februaries use the 29-day mapping (medieval scribal practice around the bissextile varied).