Archaeological investigations from 1988 to 2002 indicate that Cahal Pech Maya site was first settled sometime around 1200 B.C. and abandoned around 800 -900 A.D. The site is particularly important for the information it has provided on the earliest Maya settlers of western Belize. Early cultural remains, for example, suggest that the site’s first inhabitants were relatively sophisticated. They built large circular platforms that were used for ceremonial purposes, they carved many Mesoamerican or Olmec-like symbols on their pottery, imported jade and obsidian from Guatemala, modeled many figurines in the form of female individuals, and produced decorative beads that were made from Conch shells brought from the Caribbean coast. (source)
During the Late Preclassic period (300 B.C. – 300 A.D.) Cahal Pech became one of the most important centers in the Belize River Valley region. A relatively large temple (Structure B-4) from this phase has been conserved and can be seen at the site. Also at Cahal Pech, and dating to this phase, is the earliest carved stela yet recovered in Belize. The stela depicts a human individual within the maw (mouth) of a jaguar or monster and may represent one of the early rulers of the site. (source)
Unlike most of the other large sites in the Belize River Valley, Cahal Pech was abandoned sometime during the latter part of the 9th century A.D. Why did this decline occur earlier here than at other regional centers? Possibly because the site was conquered by a more powerful neighbor and its inhabitants were forced to switch allegiance to their new overlord. Despite its fall, however, it appears that during the Terminal Classic (A.D. 900-1000) some people either continued living in the main courtyard or periodically visited the once sacred and important center to conduct rituals in the plaza. The latter is indicated by large deposits of effigy whistles, ceramic vessels, projectile points, and deer bones that were discovered flanking the stairways of all the buildings in Plaza A. (source)
If you like these Maya Ruins in Belize, check out Tikal Maya Site in Guatemala.