Ray Tomlinson died aged 74 / AP

The father of email plucked the sign out of relative obscurity — and probably saved it from dying off entirely

Ray Tomlinson, the inventor of email who has died at 74, also gave new meaning to something at once more recognisable and much smaller — the humble @ sign.

Nobody is really clear where the symbol, which now sits in the middle of email addresses and the beginning of Twitter arguments, originally came from.

But it is now one of the most-used characters in the world, and has even been inducted into the New York Museum of Modern Art.

But it is thought, at least by some, to have begun its life in the sixth or seventh century. Then it was used as a way of writing with just one stroke the word “ad”, which means “at” or “to” in Latin.

From there it would go on to take other meanings, such as a way for Venetian traders to signify “amphora” — a terracotta vessel that was a symbol of measurement.

But it kept its meaning as a way of writing “at”, too. It was included in the first typewriters as a way of expressing that, and that meant that it carried on into computers, too.

That was where it came into its first modern meaning: a way of saying “at” that was used by accountants and other commercial workers. But it was largely unused, included on the keyboard but not used by many people at all.

It was there that Ray Tomlinson picked it up, while he was working on the early version of email at ARPAnet.

The @ was perfect for the logic of email: as they have continued to be, email addresses then were made up of a person’s name and then their institution, so it made sense for those two things to be split up by something that meant “at”.

It was also chosen precisely because it wasn’t being used. It sat on every keyboard, meaning that it could be easily added into computing systems, but people rarely actually clicked the key.

The symbol has never got a name — it’s almost always read aloud as “at”, but people tend to call the letter itself the “at sign”, “at symbol” or even “commercial at”. The Observer referred to it as the “asperand” — though neither that or any other alternative has really caught on.

The symbol went on to be inducted into MoMA in 2010. The museum accepted that it wouldn’t actually be able to acquire the symbol, but said that the importance of the symbol showed how powerful it was as a design.

That meant that its place in history was confirmed — if it wasn’t already, by its use in billions of emails and millions of tweets every day. But it could easily have dropped into obscurity without Mr Thompson.

“It is a symbol that probably would have gone away if not for email,” Joyce Kuzman, a spokesperson for his company, Raytheon said.