legitimize state control over the land, labour, and resources that were essential to the survival and growth of ancient Egyptian civilization. Old Kingdom (2686–2181 BC) Major advances in architecture, art, and technology were made during the Old Kingdom, fueled by the increased agricultural productivity and resulting population, made possible by a well-developed central administration. Some of ancient Egypt's crowning achievements, the Giza pyramids and Great Sphinx, were constructed during the Old Kingdom. Under the direction of the vizier, state officials collected taxes, coordinated irrigation projects to improve crop yield, drafted peasants to work on construction projects, and established a justice system to maintain peace and order. With the rising importance of central administration in Egypt, a new class of educated scribes and officials arose who were granted estates by the king in payment for their services. Kings also made land grants to their mortuary cults and local temples, to ensure that these institutions had the resources to worship the king after his death. Scholars believe that five centuries of these practices slowly eroded the economic vitality of Egypt, and that the economy could no longer afford to support a large centralized administration. As the power of the kings diminished, regional governors called nomarchs began to challenge the supremacy of the office of king. This, coupled with severe droughts between 2200 and 2150BC, is believed to have caused the country to enter the 140-year period of famine and strife known as the First Intermediate Period. First Intermediate Period (2181–2055 BC) After Egypt's central government collapsed at the end of the Old Kingdom, the administration could no longer support or stabilize the country's economy. Regional governors could not rely on the king for help in times of crisis, and the ensuing food shortages and political disputes escalated into famines and small-scale civil wars. Yet despite difficult problems, local leaders, owing no tribute to the king, used their new-found independence to establish a thriving culture in the provinces. Once in control of their own resources, the provinces became economically richer—which was demonstrated by larger and better burials among all social classes. In bursts of creativity, provincial artisans adopted and adapted cultural motifs formerly restricted to the royalty of the Old Kingdom, and scribes developed literary styles that expressed the optimism and originality of the period. Free from their loyalties to the king, local rulers began competing with each other for territorial control and