In the Bible, this region was known as Ammon or the Ammonite Kingdom. Rabbath Ammon, great city of the Ammonites in the Old Testament, was the capital of the kingdom and famous for its springs and citadel. King David sent Joab, head of the Israelite army, to besiege Rabbath, after being insulted by King Nahash. On taking the town, David burnt many of the inhabitants alive in a brick kiln. 

The ancient Semitic name of Amman was first changed to Philadelphia, Greek for brotherly love, by Ptolemy the Second, who reigned from 283 to 246 B.C. and occupied and rebuilt the city. He was supposedly given the nickname of Philadelphus, so it was named Philadelphia after him. 

During the Roman period, Herod took the city in 30 B.C. and it became an important center along the trade route from Syria to the Red Sea. 

Later in Byzantine times, it was the seat of the Christian Bishops of the area. Its importance declined during the 10th century, gradually being reduced to nothing more than a village, until a colony of Circassians settled here in 1878. By the early 20th century there were only about 2000 inhabitants and for almost a century it became little more than a stopping place on the Damascus to Medina railway. 

In 1921, Emir Abdullah made it his headquarters, so it became the central, administrative town and capital of Transjordan. With the foundation of the Hashemite Kingdom of Jordan in 1946 it continued as capital of the Kingdom. Following the troubles in their land west of the Jordan in 1948, many Palestinians settled in the city.