The Tetrapylon (also called Chalkoun) was the main landmark in the south-western quarter of Constantinople, built by Constantine I (r. 306-337). It marked the place where the Mese (Divan yolu) intersected with the avenue between the Golden Horn and Harbour of Julian (Uzun Çarşı) (Bogdanović, 2008).
Based on its location near the Mese, it seems plausible that this cistern was supplied by the Valens Waterway.
Literary evidence
The 7th-century Chronicon Paschale tells us that Phocas built a large cistern near this landmark and the Church of Forty Martyrs in 609 (Crow et al., 2008, p. 19). The archaeological remains of the cistern in the vicinity of this location (F7/1) has been dated to the 6th century, and not to the reign of Phocas (Crow et al., 2008, p. 128).
Archaeological evidence
This cistern identified as the cistern near the Bronze Tetrapylon lies next to Kara Mustafa Pasha Madrassa (Yeniçeriler Cd.). According to Janin, 1964, p. 214, this cistern measures 23,95 m × 16, 50. It contains 24 columns (arranged 6 × 4).
According to Altuğ, 2013, 364-365, this cistern's rectangular plan measures 12.26 × 9.78 m. The walls and vaults are covered with waterproof plaster. There are 6 marble columns; all columns are of the same type/measurement. The ground level has risen due to the accumulated rubble on the floor. There is Greek graffiti on the columns. The cistern has sail vaults, and the structure is dated to the early Byzantine period. The cistern sustained damage in 1969 due to building activities on top of it.
