Ever since the first Roman soldiers in Britain began to place dried beans on piece of paper marked with roman numerals on it, and the First Spear called numbers at random in latin: XXIII!, IV!, XXXVIII! The number had been 90. Yes, even the lowliest Roman grunt could count to 90!
Decimush Battyartus, a legionary from the XIth (9th) Legion based in Verulamium (St Albans) was sent on a scouting expedition to Wales. Now Wales was a notorious place in Britain, then as now, for its fearsome warriors, mist-shrouded valleys and mountain tops, aggressive sheep, and scary 1000 voice male choirs. Oh yes, and there were also Druids there. Specialising in wearing white bed-sheets with mistletoe crowns, in communing with nature, Elm-hugging, and human sacrifices.
Decimush was separated from the rest of his cohort at what is modern day Swansea, and was ambushed by sickle-wielding Druids. Decimush cracked a few jokes in Welsh (he'd learned the language while in Londinium) such as... "Why did the Roman legion bring back so many sheep following their victory in Cardiff? War Brides!!". And "How does a Welshman express his love? He says-I love ewe". He then sung the Welsh hymn- "Wales, Wales, where men are men and the sheep are nervous". The Druids found this faintly amusing and in return the Druids didn't sacrifice him, but instead taught him the national game Rugby-bingo. This involved standing 90 numbered Welshman in a line, all holding a leek, and then allowing a ewe to wander among them. As a person had their leek chewed by the ewe, they shouted their number, rugby-tackled the ewe to the ground, and left. The last man standing with an ewe-unchewed leek was declared the winner.
When Decimush returned to his garrison, he told his mates about the game, and they decided to try a variant of it whereby 15 numbers between 1 and 90 were marked on pieces of paper, and then marked off with dried beans as the First Spear called out numbers at random. The first games were a bit shaky because the First Spear had an appalling memory and kept forgetting which numbers he had already called, and kept repeating them, much to the annoyance of the players trying to secure a win.
Upon his return to Rome, the First Spear, whose name was Lottus Bingus Housey-Housex introduced the game to the rest of Italy, where as "Lotto" it gained in popularity to such an extent, that it was featured in the AD95 Gladitorial Games at Capua. The prize for the eventual winner at those games was allowed to try his luck in the arena against a crazed sheep in armour, armed only with a short blunt stabbing implement, known as an Autodaubius, and a leek.