Simplify the following text for a Grade 9 native English-speaking person.
Original: Caid is believed to have influenced the modern sport of Gaelic football the rules of which were officially published in 1887 and is now organized and governed by the Gaelic Athletic Association ( GAA ) as an amateur sport .
Simplified: Some people believe that caid has influenced the modern sport of Gaelic football the rules of which were officially published in 1887 .