Harran, or Carrhae as the Romans called it, is one of the oldest cities in the world. The city in northern Mesopotamia was already important in the third millennium BCE, when it played a role in the Assyrian trade on Anatolia. It was also famous for a temple of the Moon god, Sin, who was venerated by -among many others- the Babylonian king Nabonidus (r.550-539). On a Roman monument in Ephesus, commemorating Lucius Verus‘ Parthian victory (photo), Harran is shown with a banner with a moon on it.
In the Bible, it is mentioned as one of the towns where Abraham stayed on his voyage from Ur to the promised land (Genesis, 11.31). The well where a servant of Abraham met Rebecca, who was to become the wife of Isaac (Genesis, 24), is still shown today.
In Roman history, Harran/Carrhae (satellite photo) became notorious because general Crassus was defeated here by the Parthians, in 53 BCE. It is often said that the desert land played a role, but Harran is in fact situated in the valley of the river Balikh. The story is told in Plutarch‘s Life of Crassus, ch.16ff.