Callirrhoe is known in ancient literature for its thermal springs, because it was visited by King Herod according to Josephus shortly before his death in 4 BCE, as a final attempt to be cured or relieve his pains.

Callirrhoe is referred by Pliny the Elder (Natural History, 70-72), Ptolemaeus (Geography 15,6) and Solinus (De mirabilibus mundi 35,4)[4] as well as in a Midrash.

More probable is its derivation from an unattested original form al-Ayn az-Zahra ("the shining spring"), acting as a direct calque of the Greek.

[10] Callirrhoe is identified as the present day oasis 'Ein ez-Zara, laying on the eastern shore of Dead Sea south of Wadi Zerka Ma'in in Jordan.

It was founded circa 1st century BCE and excavations between 1985 and 1989 were directed by August Strobel on behalf of the German Evangelical Institute for the Ancient Holy Land.