the Neo-Assyrian period, an extensive hierarchy within the provincial administration is attested. At the bottom of this hierarchy were lower officials, such as village managers (rab ālāni) who oversaw one or more villages, collecting taxes in the form of labor and goods and keeping the administration informed of the conditions of their settlements, and corvée officers (ša bēt-kūdini) who kept tallies on the labor performed by forced laborers and the remaining time owed. Individual cities had their own administrations, headed by mayors (ḫazi’ānu), responsible for the local economy and production. Some regions of the Assyrian Empire were not incorporated into the provincial system but were still subjected to the rule of the Assyrian kings. Such vassal states could be ruled indirectly through allowing established local lines of kings to continue ruling in exchange for tribute or through the Assyrian kings appointing their own vassal rulers. Through the ilku system, the Assyrian kings could also grant arable lands to individuals in exchange for goods and military service. To overcome the challenges of governing a large empire, the Neo-Assyrian Empire developed a sophisticated state communication system, which included various innovative techniques and relay stations. Per estimates by Karen Radner, an official message sent in the Neo-Assyrian period from the western border province Quwê to the Assyrian heartland, a distance of 700 kilometers (430 miles) over a stretch of lands featuring many rivers without any bridges, could take less than five days to arrive. Such communication speed was unprecedented before the rise of the Neo-Assyrian Empire and was not surpassed in the Middle East until the telegraph was introduced by the Ottoman Empire in 1865, nearly two and a half thousand years after the Neo-Assyrian Empire's fall. Military The Assyrian army was throughout its history mostly composed of levies, mobilized only when they were needed (such as in the time of campaigns). Through regulations, obligations and sophisticated government systems, large amounts of soldiers could be recruited and mobilized already in the early Middle Assyrian period. A small central standing army unit was established in the Neo-Assyrian Empire, dubbed the kiṣir šarri ("king's unit"). Some professional (though not standing) troops are also attested in the Middle Assyrian period, dubbed ḫurādu or ṣābū ḫurādātu, though what their role was is not clear due to the scarcity of sources. Perhaps this category included archers and charioteers, who needed more extensive training than normal foot soldiers. The