Assyrian period, the government was in many respects an oligarchy, where the king was a permanent, albeit not the only prominent, actor. The Old Assyrian kings were not autocrats, with sole power, but rather acted as stewards on behalf of the god Ashur and presided over the meetings of the city assembly, the main Assyrian administrative body during this time. The composition of the city assembly is not known, but it is generally believed to have been made up of members of the most powerful families of the city, many of whom were merchants. The king acted as the main executive officer and chairman of this group of influential individuals and also contributed with legal knowledge and expertise. The Old Assyrian kings were styled as iššiak Aššur ("governor [on behalf] of Ashur"), with Ashur being considered the city's formal king. That the populace of Assur in the Old Assyrian period often referred to the king as rubā’um ("great one") clearly indicates that the kings, despite their limited executive power, were seen as royal figures and as being primus inter pares (first among equals) among the powerful individuals of the city. Assur first experienced a more autocratic form of kingship under the Amorite conqueror Shamshi-Adad I, the earliest ruler of Assur to use the style šarrum (king) and the title 'king of the Universe'. Shamshi-Adad I appears to have based his more absolute form of kingship on the rulers of the Old Babylonian Empire. Under Shamshi-Adad I, Assyrians also swore their oaths by the king, not just by the god. This practice did not survive beyond his death. The influence of the city assembly had disappeared by the beginning of the Middle Assyrian period. Though the traditional iššiak Aššur continued to be used at times, the Middle Assyrian kings were autocrats, in terms of power having little in common with the rulers of the Old Assyrian period. As the Assyrian Empire grew, the kings began to employ an increasingly sophisticated array of royal titles. Ashur-uballit I was the first to assume the style šar māt Aššur ("king of the land of Ashur") and his grandson Arik-den-ili ( 1317–1306 BC) introduced the style šarru dannu ("strong king"). Adad-nirari I's inscriptions required 32 lines to be devoted just to his titles. This development peaked under Tukulti-Ninurta I, who assumed, among other titles, the styles "king of Assyria and Karduniash", "king of Sumer and