Birtha (Mesopotamia) bastions are quite traceable. There are the ruins of a vaulted secret staircase, leading down from the heart of the citadel to the water's edge. Birtha (Mesopotamia) Birtha () was an ancient fortress on the river Tigris, which was said to have been built by Alexander the Great. It would seem, from the description of Ammianus, to have resembled a modern fortification, flanked by bastions, and with its approaches defended by out-works. Shapur II here closed his campaign in 360, and was compelled to retire with considerable loss. D'Anville and Edward Gibbon both identify Birtha as modern-day Tikrit, Iraq. The
Dara (Mesopotamia) the country of the Arabs from the inroads of the Persians and Saracens". Masons and workers from all over Mesopotamia were gathered and worked with great haste. The new city was built on three hills, on the highest of which stood the citadel, and endowed with great storehouses, a public bath and water cisterns. It took the name "Anastasiopolis" () and became the seat of the Roman "dux Mesopotamiae". According to Procopius, the hasty construction of the original walls resulted in poor quality, and the severe weather conditions of the region exacerbated the problem, ruining some sections. Thus Byzantine Emperor