From Wikipedia
Mayan Prophesies Of Copan
The fertile Copán River valley was long a site of agriculture before the first known stone architecture was built in the region about the 9th century BC.
A kingdom seems to have been established in Copán in 159. It grew into one of the most important Maya sites by the 5th century. Large monuments dated with hieroglyphic texts were erected in the city from 435 through 822.
Xukpi was one of the more powerful Maya city states, a regional power, although it suffered a catastrophic defeat at the hands of its former vassal state Quirigua in 738, when the long-ruling Xukpi ruler Uaxaclajuun Ub'aah K'awiil (18 Rabbit) was captured and beheaded by Quirigua's ruler K'ak' Tiliw Chan Yopaat (Cauac Sky). Though Copán's rulers began to build monumental structures again within a few decades. Although many theories have been proposed to explain the decline of most of Mayan civilization by ~900 AD (Copán's last known dynastic monuments date to 822 AD), the lack of data has prevented any firm conclusions . Popular hypotheses include invasion by foreign forces, revolutions that swept the region, unsustainable population growth, and environmental and agricultural disasters such as soil depletion, overuse of land, and climatic deterioration .
The area of Copán continued to be occupied after the last major ceremonial structures and royal monuments were erected, but the population declined in the 8th century - 9th century from perhaps over 20,000 in the city to less than 5,000. The ceremonial center was long abandoned and the surrounding valley home to only a few farming hamlets at the time of the arrival of the Spanish in the 16th century.
