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
Amida (Mesopotamia) of Amida and Diyarbakir, see the Diyarbakır article. Amida (Mesopotamia) Amida (, , ) was an ancient city in Mesopotamia located where modern Diyarbakır, Turkey now stands. The Roman writers Ammianus Marcellinus and Procopius consider it a city of Mesopotamia. The city was located on the right bank of the Tigris. The walls are lofty and substantial, and constructed of the recycled stones from older buildings. Amid(a), also known by various names throughout its long history, was established as an Aramean settlement, circa the 3rd millennium BC, later as the capital of Bit-Zamani. The oldest artefact from Amida is the