At about the same time, sundials were developed, likely marked first at noon, sunrise and sunset. In ancient Sumer and Egypt, numbers were soon used to divide the day into 12 hours; the night was similarly divided. In Egypt there is not as much seasonal variation in the length of the day, but those further from the equator would need to make many more modifications in calibrating their sundials to deal with these differences. Ancient traditions did "not" begin the day at midnight, some starting at dawn instead, others at dusk (both being more obvious).