The Torah Portions were arranged to make sure that the Torah was read on Shabbat when everyone was present in the synagogue. There are fifty four to ensure that there are enough to fill every Shabbat in the year (that does not coincide with the Festivals), even on leap years when there are en extra four weeks in the year. In Talmudic times there were two different schools of thought as to how long it should take to complete the cycle of Torah readings. In the Land of Israel the cycle took three and a half years, in Babylon the cycle was only one year. For over one thousand years the accepted custom has been to complete the entire reading of the Torah in one year.
