The origins of card games are more complicated than games like slots, and can’t be traced to any single game, and blackjack is no different. The 17th century French game Vingt-et-Un, or "21" is seen as one of the most likely candidates as the early roots of blackjack. The game came to to North America with European immigrants in the late 19th century, and naturally made its way to Las Vegas, Nevada when gambling became legal in the state. The game was slow to take off, as most Americans preferred craps and roulette . The casinos tried different bonus schemes to make the game more attractive to players. One such bonus was a 10 to 1 payout out when the player made a 21 with the ace of spades and a black jack (either the jack of clubs or the jack of spades,) and from there we get the name "Black Jack". Blackjack’s popularity grew quickly, 1930's the game was the third most popular casino game in Las Vegas, and was second only to craps by the 1950‘s. With the increasing popularity of blackjack, mathematically proven strategies for the game began to surface. Thorpe, the real pioneer of blackjack strategy, paved the way for many card-counting blackjack players during the later half of the 20th century. More complex strategies were able to be developed with the help of computer simulations, skilled players - or teams of players - could take advantage of the mathematically proven theories and make lots of money before they were banned from the casinos. Today, with the increasing popularity of online casinos, blackjack has become one of the most popular casino card games of all time.