Incorrect; originally in the UK there were two codes - association football and rugby football.
Not true either. Originally, there was just football played under a wide variety of local rules. I'm talking about organised football, played on marked-out fields, with referees or umpires etc., not more ancient inter-village free-for-alls. There were some local codes which allowed running with the ball and some which didn't, but all codes allowed handling.
Posh schools took up football only later, with the advent of "muscular christianity" and all that crap. Like villages and regions, they each developed their own varied rules, but Rugby school was the only one which allowed running with the ball. They later claimed to have initiated this when they perceived "their" game as in danger of being taken over by working class oiks. But they lied. The working class oiks' great-grandads had been doing the same in many places long before any sort of football was played at posh schools at all. Rugby school may have changed its rules at some stage, but they didn't invent the "running" code of football, as they claim.
The tale about William Webb Ellis is utter bollocks which can't stand up to 5 seconds' historical analysis. It was invented many years after it allegedly happened, after William Webb Ellis had died (he never mentioned it himself) by an old man who claimed to have been at the school at the time but wasn't, to serve the political purpose of asserting class interests and "ownership" of the game. Pure propaganda, and an illustration of Goebels' dictum about repeating a lie often enough.
When specific football clubs were first formed there was still a variety of rules around, in the same two broad groups which were now being codified. It was common for clubs to play under the "association" rules one week and the "rugby" rules the next week. Fixtures between clubs were often arranged before it had been agreed which set of rules would be used.
There were two varieties of the "association" rules -those which allowed "hacking" and those which didn't, and this was a matter of huge contention. The posher players and clubs usually favoured "hacking" and denounced the introduction of shin pads as protection. Only cads and cowards would resort to such sneaky tricks, not gentlemen from good schools and scions of the empire blah, blah, blah.
It was at the stage of clubs playing different codes on alternate weeks that a number of splits happened. For example, Manchester United originated as a breakaway from Salford Football Club (now rugby league) by guys who wanted to play under association rules
every week.
What few football people realise is that it took quite some time for the FA to ban handling the ball and establish special rules for the goalkeeper only. All the early FA cup finals, for example, were played under the old handling rules. The ball could be caught and struck with the hand, but not thrown, and you couldn't run with it. Much like Gaelic football, in fact, which preserves the hand-pass (punched out of the hand, not thrown) as does it's ill-begotted progeny, Aussie rules.
Many Irish people have a misconceived notion of the uniqueness of their code and don't realise how similar it is to early association football (or vice-versa). There's been a lot of politics and propaganda over that one, too! It's really only the scoring system, not the method of play, which distinguishes Gaelic football from early "soccer".
Once handling had been abolished, association football in England was still nothing like the modern game. In fact, the abolition of handling was arguably a retrograde step, leaving only individualistic kick and rush, with or without "hacking". The "passing game" (as it was called) was developed in Scotland. It was a genuine team game, more enjoyable to play and interesting to watch. Teams which adopted it could run rings those still playing the old kick and rush game. It quickly caught on and became the way the game is now played all over the world.
Not as simple or clear-cut as people often believe, is it?