The casino set the standards for roulette in Europe, and roulette remained exclusive to Monte Carlo until 1933.
When gambling was outlawed in Germany the inventor of the single zero machine (Louis Blanc) accepted an invitation to go to Monaco to establish and operate a casino. 'In the mid 19th century the single zero game was invented in France, this reduced the casino's edge thereby increasing the odds of the player.
This led to some confusion for players and the color green was introduced for the zero and double zero to alleviate the confusion. This game contained all of the features that we have today with the one exception, the single zero was colored red while the double zero was colored black. The first games that we would recognize as modern roulette were introduced in Paris casinos around the end of the 18th century. 'Several early versions of a wheel and spinning ball were invented in the 17th and 18th centuries in Europe.
There are stories that the game was invented in China and brought to Europe by traders who were trading with the Chinese. 'Roulette history is hard to come by because the origin of roulette is lost, and there was likely some form of a wheel based game going back almost as far as the origin of the wheel itself.