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
Mesopotamia in Classical literature and the numbers associated with them are probably corrupt. It is different with the 7th and 8th dynasties as given by Ptolemy in the Canon of Kings in his "Almagest", which prove to have been recorded faithfully: Mesopotamia in Classical literature Before the decipherment of cuneiform text, knowledge of the history of the ancient Mesopotamia was mostly dependent upon classical authorities and the Hebrew Bible. These testimonies were scanty and confused for times predating the 7th century BCE. Had the native history of Berossus survived, this may not have been the case; all that is known of the Chaldaean historian's