Piedras Negras is the modern name for a ruined city of the Pre-Columbian Maya civilization located on the north bank of the Usumacinta River in the Peten department of Guatemala. The name "Piedras Negras" means "Black Stones" in the Spanish language. The ancient Maya language name seems to have been have been Yokib ("Great Gateway" or "The Entrance"). Piedras Negras seems to have been an independent city-state for most of the Classic Period, although sometimes in alliance with other states of the region and perhaps paying tribute to others at times. It had an alliance with Yaxchilan, some 40 km up river. Ceramics show the site was occupied from the mid 7th century BC to 850 AD. Its most impressive period of sculpture and architecture dated from about 608 through 810, although there is some evidence that Piedras Negras was already a city of some importance earlier. The artistry of the sculpture of the late classic period of Piedras Negras is considered particularly fine. Before the site was abandoned, some monuments were deliberately damaged, including images and glyphs of rulers defaced, but images and glyphs of dieties left intact, suggesting a revolt or conquest by people literate in Maya writing.