Concept
Calendar Round
The combination of Tzolk’in and Haab’. A paired date repeats after 18,980 days, which is 52 Haab’ years, about 51.96 tropical years.
Unknown Maya scribe; photograph of a public-domain manuscript, “Dresden Codex, page 49”, Public domain, via Wikimedia Commons
73 × 260 = 52 × 365. The arithmetic is exact. The recurrence gave a human-scale commemorative cycle without being a historical count. For history the Maya used the Long Count.