Simplify the following text for a Grade 4 native English-speaking person.
Original: Hull City Association Football Club was founded in June 1904 . For some years previously , attempts had been made to found a football club , but this proved difficult because the city was then dominated by rugby league teams such as Hull F.C. and Hull Kingston Rovers .
Simplified: Hull City A.F.C. are an English football club who are based in Kingston upon Hull .