Archaeological exploration of the area began in the nineteenth century, with excavations undertaken by Charles Warren in 1867. Warren was sent by the Palestine Exploration Fund. Warren conducted an excavation of the area south of the Temple Mount and recovered a massive fortification. The finding led him to conduct more excavations at the area south of the Temple Mount. There he revealed a vertical shaft descending from a slanted tunnel to an apparent water source. He suggested that the shaft was used to supply water to the city, which he believed was the old biblical city of David. Today this shaft is called after its discoverer Warren's shaft, but his interpretation has been proven wrong, as the shaft is not man-made and had not yet been discovered by Jerusalem's inhabitants in the 10th century BCE.