Dating to around 300 B.C., Petra, in southern Jordan, was the capital of the Nabatean Kingdom. The Nabataeans, a nomadic Arab people, were able to live in the desert environment due to their skills in rainwater harvesting, agriculture, and stone carving. The Treasury (Al-Khazneh in Arabic) is believed to be built as a mausoleum and crypt for Aretas IV Philopatris, one of Nabatean Kings, at the beginning of the 1st century AD.