When did football become a sport?

Answer 1

The English FA wrote the rules for Football in 1863...so probably from that point.

The Football Association (FA) legalised professionalism in 1895. Professional players from the working class had been hired to play football since the 1870s, and their presence caused anxiety among middle-class players, who believed that these professional players were only interested to be paid to win. Aston Villa was the first top-tiered football club that openly hired professional players of the time, although most of the professionals were hired by clubs that were located in the industrial North. It occurred to the Old Boys in the FA that most clubs wanted to win in their leagues, and in order to do that, they had to hire professional players. As a result, they passed their legislation in 1895 on condition that clubs had to follow the transfer window rules and the transfer fee system as a means to limit the transferability of the players.