The excavations undertaken under the cathedral during 17 months in 1994–1995 covered 316 square metres (3,400 sq ft) and revealed many archaeological layers that allowed a historical timeline of the church and its surroundings to be constructed.

[8] In 1994, archaeological excavations undertaken within and in the vicinity of the Saint George cathedral before the initiation of restoration works unveiled a number of artifacts and vestiges spanning the Hellenistic, Roman, Byzantine, Medieval and Ottoman eras.

[2][9] A committee was formed under the patronage of the Greek Orthodox Archdiocese of Beirut to oversee the excavations and the creation of the Saint George archaeological crypt museum.

The founding committee was headed by archaeologist Leila Bader who served as the director of the American University of Beirut Archaeological Museum and included Nabil Azar, Yasmine Macaron Bou Assaf, Katia Neeman Salha and Rita Kalindjian.

[10] The museum consists of a crypt running under a part of the cathedral where visitors walk through 12 stops showcasing the different archaeological and historical layers.

[2][9] The museum has a surface area of 250 square metres (2,700 sq ft), it is accessible through a breach in the cathedral's foundation wall and a stairwell built in front of the church's northern side.

[2][9] The display includes a number of finds such as oil lamps, smoking pipes, pottery, statuettes and Christian vessels and ornaments.

Other vestiges kept in-situ include parts of the older churches' altars and apse, mosaics, stone engravings, tombstones and columns, some of which belong to the old city's Cardo maximus.