The Man Who Broke the Bank at Monte Carlo — Six Times in Three Days

In July 1891, an English con man named Charles Deville Wells arrived at the Casino de Monte-Carlo with £4,000 — borrowed, fraudulently acquired, and desperately needed to fund his latest scheme. Over three days, he sat at a single roulette table and won. He won so consistently that the casino was forced to carry in a fresh supply of chips six separate times, each delivery marked by the ceremonial covering of the table with a black cloth — "breaking the bank."

He left with £40,000. A Charles Coborn song about him became one of the most popular of the Victorian era. The Prince of Wales sent agents to observe his next visit. The world wanted to know: was it mathematics, or was it magic?

What "breaking the bank" actually means

Each roulette table at Monte Carlo operated with a fixed reserve of chips — its "bank" — typically worth one million francs. When a player's wins depleted this reserve, play stopped while more chips were brought from the main casino vault. The table was covered with a black cloth during the transfer. This theatrical pause was "breaking the bank." It said nothing about the casino's total solvency — only that one table's operating reserve had been exhausted.

The probability of Wells' run

Wells reportedly won 23 out of 30 consecutive bets on even-money wagers (red/black). With European roulette odds:

p = 18/37 ≈ 0.4865 (probability of winning one red/black bet)
q = 19/37 ≈ 0.5135

P(X ≥ 23 out of 30) = Σ C(30,k) × p^k × q^(30-k) for k = 23 to 30

P(X ≥ 23) ≈ 0.000374 (approximately 1 in 2,670)

In a single session: extremely unlikely.
Across the millions of sessions played in Monaco annually: expected
to occur roughly every few years at some table somewhere.

Was it a system?

Wells claimed to have a "secret system." He wrote a pamphlet selling it for £1. The system was Martingale — doubling bets after each loss. Martingale cannot generate a long-term edge. It manipulates the distribution of outcomes without changing expected value. Wells was either extraordinarily lucky or — as was later suspected — the wheel was biased.

Wheels of the era were often imperfectly balanced. A slight bias toward certain sectors could give an observant player a genuine edge. Joseph Jagger, a British engineer, had done exactly this at Monte Carlo in 1873, hiring six clerks to record every spin across six wheels until he identified a biased one. He won the equivalent of $9 million in modern money before the casino responded by nightly rotating wheel frets — a practice still used today.

The end of the story

Wells returned to Monte Carlo twice more, winning again before eventually losing everything. He was later convicted of fraud in England — not for the Monte Carlo exploits, which were entirely legal, but for selling fictitious patents and investment schemes. He died in poverty in Paris in 1926.

The Casino de Monte-Carlo still operates today. Its mathematical edge has never been broken in the true sense — the house expected value is precisely what the wheel geometry dictates. Charles Wells broke the operating reserve of a single table, several times, through a combination of luck, possible exploitation of a biased wheel, and an excellent sense of theatre. The bank was broken. The house edge was not.