Simplify the following text for a Grade 4 native English-speaking person.
Original: In the English-speaking world , the character called `` Father Christmas '' influenced the development in the United States of Santa Claus , and in the United Kingdom and elsewhere , most people now consider them to be interchangeable . However , although `` Father Christmas '' and `` Santa Claus '' have for most practical purposes been merged , historically the characters have different origins and are not identical .
Simplified: Father Christmas is the British name for Santa Claus .