A Classic Maya city on the Pasión River that was the largest settlement in its region in the Late Preclassic, was conquered and reduced to a vassal of the Dos Pilas-based Petexbatún kingdom in AD 735, and — after that kingdom's collapse — was revived from 830 by an intrusive ruling line from Ucanal, becoming one of the last Classic Maya centers still dedicating monuments.
Enjoyed a second flourishing (c. 830-890s) under its new dynasty and kept raising dated stelae into the early 10th century, well after the Classic Maya collapse had engulfed most of the Petén region, before its eventual abandonment.
The atlas holds 5 border frames for Seibal (Ceibal) — the shape you scrub through changes in 300 · 359 · 550 · 751 · 901.
The Harvard Peabody Museum's definitive multi-volume site-report series on Seibal's excavation, ceramics, and monuments.