Complex sentence: In the United Kingdom, "vacation" once specifically referred to the long summer break taken by the law courts and, later, universities--a custom introduced by William the Conqueror from Normandy where it facilitated the grape harvest.
Split into simpler sentences: In the United Kingdom, "vacation" once specifically referred to the long summer break taken by the law courts and then later the term was applied to universities. The custom was introduced by William the Conqueror from Normandy where it facilitated the grape harvest.