In Arabic, the name Qasr al-Abd means “castle of the slave (or servant).” No one knows for sure how it got this name. According to local legend, mentioned in the early accounts of both Claude Conder and Howard Crawford Butler,a the story goes as follows:
One day a local prince goes off to participate in the Hajj, the annual Muslim pilgrimage to Mecca, and leaves his beautiful daughter in the care of his faithful slave. The slave, of course, falls in love with the daughter, who then agrees to marry him, but only if he builds her a fine castle. In his great zeal, the slave manages to cut enormous stones from the cliffs and uses them to build the beautiful castle. But just as he is finishing and placing the castle’s last stone, he hears the prince on his horse returning from the Hajj. The slave is so frightened and distraught that he drops the heavy stone on himself and dies.
The origin of the name may also go back to the Tobiads. Under the Ptolemies, the Tobiads were ministers (in Hebrew, avadim, or “servants”) responsible for tax collection, while before that the family had served as land administrators for the Persian king. Just as the English word “secretary” can be someone high or low on the pecking order, the Semitic word “servant/slave” has an even wider semantic range. As such, the name could have been given to the castle by Hyrcanus or one of his descendants.