Although archeologists have found evidence of human occupation at Jerash as long as 6,500 years ago, and the city was conquered by Alexander the Great in the 4th century BCE, it was not until the Romans took control in 63 BCE that a great city began to develop. After conquering the area, Emperor Pompey declared Jerash (also known as Gerasa) to be part of the Decapolis, a confederation of ten Greco-Roman cities that included Philadelphia (present-day Amman) and Damascus.
The fortunes of Jerash rose in 106 CE when Roman Emperor Trajan annexed the wealthy Nabataean kingdom (at Petra), forming the Province of Arabia and bringing trade and wealth to the city. In 129 CE Jerash was visited by Emperor Hadrian, and a large Triumphal Arch was erected at the southern end of the city to mark the occasion.
Jerash reached its golden age in the third century CE and many of the grand structures that we see today date from this period. As trade routes shifted (mainly to the sea), Jerash's importance and fortunes began to decline.
By the middle of the 5th century, Christianity had swept through the area and visitors today can see evidence of churches built in the city during this period. In the 7th century, Jerash was invaded by the Persians, followed by the Muslims. An earthquake a century later further hastened the city's decline. By the time of the Crusades, Jerash was considered uninhabited.
Over succeeding centuries, sands covered the remains of Jerash and preserved it until its rediscovery in 1806 and excavations that began in 1925. Because they lay buried so long, the ruins at Jerash are among the best preserved from the Roman era.
The slide show above also includes some Roman ruins from the ancient city of Philadelphia (present-day Amman, the capital of Jordan). Included are the Temple of Hercules that overlooks the modern city, and a large amphitheater and accompanying Odeon (a smaller theater) located right in the heart of modern Amman.