Arsenal, as we all know, are a team of firsts. They were the first team to put squad numbers on shirts, in 1928 (they were worn sporadically for a few years before becoming a regular occurrence in 1933). They were the first team to wear striped socks, which Herbert Chapman thought would make Arsenal players easier to spot when they were running with their heads down. Arsenal were the first team to install floodlights and play at night. And so on.
Today marks the anniversary of another Arsenal first - 78 years ago, in 1937, Arsenal were a part of the first ever live televised football match. As opposed to today, when there are incessant pre- and post-game shows, highlight shows, etc., the Arsenal vs Arsenal Reserves match was not broadcast in its entirety, as evidenced by the BBC TV schedule for the day:
3pm: Fancy That!
3.30pm: British Movietonews
3.40pm: Football at the Arsenal
So, there was 15 minutes of Arsenal taking on Arsenal reserves before a cartoon, which was before the 4PM end of the broadcast day.
The reason Arsenal was chosen? Proximity to the BBC. It wasn't hard to haul the heavy, awkward TV equipment of the day to Arsenal Stadium, so that's what they did. After that, there was sporadic covarage - part of the FA Cup final that year was shown, and in 1938, an England-Scotland international was the first game to be broadcast in full.
The linked piece is a pretty interesting history of British soccer broadcasting - it's definitely worth a read, and definitely worth remembering that, like in many things, Arsenal were there first.