From the accounts of the Roman writer Censorinus we come to know that the Egyptians calculated their New Year based on the sighting of Sirius, the brightest amongst the stars in the night sky. New Year was declared when Sirius became visible after a period of 70 days absence. This incident was termed as the heliacal rising and it occurred sometime in the middle of the month of July just prior to the annual Nile inundation. This contributed towards keeping the farmland fertile.