Sir Captain (later General) Charles Warren (1840-1927) was sent by the Palestine Exploration Fund (PEF) in 1867 to explore Palestine (Israel) and Jerusalem. He was an engineering officer in the Corps of Royal Engineers in the British Army, and an engineer by training. Later, he served as a police officer in London.

He began his work in Jerusalem around the Temple Mount because he was prevented from exploring the Temple Mount itself by the Ottoman authorities. Following this, he excavated the area south of the Temple Mount, discovering a massive fortification there, which led him to inspect the hill area at the foot of the Temple Mount, known today as the Hill of the City of David.

He entered the Gihon Spring in October 1867, and began to explore the underground tunnels in the area. During his work, he uncovered a vertical shaft that led to a hewn tunnel connecting the spring, at the foot of the hill, with the top of the hill. He believed it to be a system designed to connect the residents of the city and the spring, with pumpg done through the same shaft. Today, this shaft is called the ‘Warren Shaft’ after its discoverer, but today we know that no water was pumped through this shaft, although the tunnel did connect the city with the water source.