"Seibal known as El Ceibal in Spanish, is a Classic Period archaeological site of the Maya civilization located in the northern Petén Department of Guatemala. It was the largest city in the Pasión River region." Source: Ancient Mayan Ruins.
"... The site was occupied from the Preclassic Period through to the Terminal Classic, with a significant hiatus. The principal phase of occupation dates to the Late Preclassic (400 BC – AD 200), followed by a decline in the Early Classic (AD 200–600). Seibal experienced a significant recovery in the Terminal Classic immediately prior to its complete abandonment, reaching its second peak from about 830 to 890, with a population estimated at 8–10,000 people."
Video from 2015. Closed captions help with this one.
A king named Wat'ul Chatel (830 - ? AD) was the last known ruler of Seibal. According to Wikipedia, his "last monument was erected in 889. This stela is also the last dated monument raised at Seibal and by 900 the city was all but abandoned, the whole region had been engulfed by the Classic Maya collapse and trade no longer flowed along the Pasión [river]-Usumacinta [river] route. Most Classic Maya capitals had already been abandoned and whatever external support Seibal had received from its overlord had vanished. By 930 AD, the site was completely abandoned."