The material basis of the Egyptian commonwealth was agriculture, regulated by the unaltering rhythm of the inundation. The names of the three seasons (of four months each) which the Egyptians distinguished were “Inundation” (middle of July to middle November), “Coming Forth” (of the seeds, or possibly of the land from the inundation, from middle November to middle March), and “Drought.” The conditions prevailing in prehistoric times, described in the second chapter, were not materially altered during the Old Kingdom. Land had to be reclaimed from the marshes. We have seen that the first king, Menes, undertook such work on a considerable scale. But the more the valley was drained, the more the need arose to distribute the inundation water so that it reached all the fields. From the beginning of the First Dynasty annual records of the height of the Nile were kept; their purpose can only have been to provide a basis for an estimate of its extent and thereby of the probable yield of the harvest. The digging of canals and the building of dikes was normally done by the central government, but there are some indications that the king encouraged the nomarchs to reclaim land by granting them the new fields which they then were allowed to settle with people from their estates. In the First Intermediate period when each nomarch had to take care of his area as best he could, one of them records: I stocked villages in this nome that were enfeebled with cattle and men of other nomes, and those who had been serfs elsewhere I made rank as notables.[163] The annual inundation with its fertilizing deposit of silt made manuring and rotation of crops unnecessary. The tax records distinguish between low land, which was regularly inundated, and high land, which came under water only when the flood was high. This land was used for grazing or truck gardening. The bulk of the arable land was left soft by the retreating inundation and could be worked with primitive wooden hoes and ploughs. Animals, mostly sheep, were used to tread in the seed, and this had to be done speedily after the land had emerged but before it became hard and dry. Six-rowed barley and emmer wheat were the main crops. Lettuce, onions, beans, and lentils were, in antiquity as now, important secondary products. Ricinus plants were grown for oil, and flax for linen.