This was a Nabatean temple, and is the only temple that remains which was actually built at Petra,
rather than being carved into the rock.

JordanJubilee.com says that "A French team has been working here for several years, and very
recently discovered a huge marble statue of Marcus Aurelius.  It is here that the head of
another statue, that of Zeus, was found which can now be seen in the Petra Museum. It is believed
that there was a hallway lined with statues, but since most of the minor ones were carved out of
sandstone they have disintegrated over the years.  The Qasr el Bint was one of the most
important temples in Petra, and was almost certainly dedicated to [the God] Dushara."