Working as a journalist in Hungary, Bíró László József, noticed that newspaper ink, in contrast to fountain pen ink, dried quickly and smudge-free. Finding that the same ink was too thick to flow into the tip in a fountain pen, he worked with his brother to develop a rolling ball in a socket that would pick up ink from a cartridge and then roll it on to paper.
During the war the brothers moved to Argentina, and today in 1943 they filed a patent and formed Biro Pens of Argentina. Their new pen was licensed for production in the UK for supply to Royal Air Force aircrew, who found that the pens worked better at altitude than fountain pens.
And what do all those Biros do? They write words, so today we're drinking an aptly named Last Word.