The great temple was first explored by Brunnow and von Domaszewski, but it was Bachmann, in his revision of the Petra city plan, who postulated the existence of a "Great Temple", aligned with the Colonnade Street, lying on the hillside to the south. He speculated that the temple was approached though a monumental Propylaeum with a grand staircase leading into a colonnaded Lower Temenos, or sacred precinct. Given the promise of the Great Temple precinct and its importance in understanding Petra's architectural and intercultural history, it is remarkable that it remained unexcavated until 1993 when the Brown University investigations began.