Simplify the following text for a Grade 14 native English-speaking person.
Original: The WWE United States Championship was originally known as the NWA United States Heavyweight Championship and began as a regional championship created by and defended in Mid-Atlantic Championship Wrestling run by Jim Crockett , Jr. .
Simplified: The WWE United States Championship was originally known as the NWA United States Heavyweight Championship of Mid-Atlantic Championship Wrestling run by Jim Crockett Promotions .