One of the most interesting texts from Achaemenid Babylonia which has been published is a contract between Gadal-iama, son of Rahîm-ilê, and Rîmût-Ninurta, son of Murašû. Amongst other things, it contains the first description of special garments meant to be worn with armour which I have ever heard of. Because there do not seem to be any good discussions online, and because the translations in books for non-specialists are often very loose, I decided to post an Akkadian text and a translation or summary online. Before I do so, I should probably explain what this contract is.
In the late first millennium BCE, the Babylonian, Persian, and Macedonian kings of Babylon all distributed land on the understanding that its holders would serve in the army when required. Men who did not hold this type of land might still serve in the army, and men who did hold it had various ways to evade, but holding such land gave the authorities a strong claim to one’s service. As is the way of such things, after a few generations the ownership of this land grew complicated, and who would serve for a particular plot debatable. While this gave the Babylonians headaches, it is very convenient for historians, since it caused parts of the system to be mentioned in legal documents. Some of these were written on clay and have survived, been excavated, and been published. The most famous of all is a letter by one Gadal-iama to Rîmût-Ninurta offering to attend a muster at Uruk if Rîmût-Ninurta provided Gadal-Iama with certain equipment. (G’s name is West Semitic, and that “ia” should probably be pronounced like English “yeah” or German “ja”, thus Germans sometimes write the name Gadal-jâma and English writers Gadalyama; the dash probably separates two West Semitic words, but I don’t know anything about that language family). We actually have not Gadal-iama’s letter but a file copy of Rîmût-Ninurta’s reply which quotes the original.
The first edition of this text was published in 1928, and since then many scholars have written about it. Many of them were more interested in philology or military affairs than military history, while the military historians were rarely able to read the original (in fact, a certain Mr. Manning relied on memory and a summary when he was finishing his MA thesis!) If one understands war and is willing to learn a bit of Akkadian, there is a great deal of useful work to be done.
Edit 2015/08/01: Added page reference to Amélie Kuhrt’s sourcebook
Further Reading: Matthew Stolper, Entrepreneurs and Empire (1985) (background information); E. Ebeling, “Die Rüstung eines babylonischen Panzerreiters nach einem Vertrag aus der Zeit Darius II.” Zeitschrift für Assyriologie und vorderasiatische Archäologie (Berlin), N.F. 16, 1952 pp. 204-13 (German translation and long commentary); Amélie Kuhrt, The Persian Empire: A Corpus of Sources from the Achaemenid Period document 14/28 p. 722 (English translation and bibliography).