The classic two-deck patience, also called Napoleon at St Helena: build down by suit one card at a time, and get all 104 cards home in a single pass through the stock.
Forty Thieves uses two 52-card decks shuffled together. Four rows of ten cards are dealt face up, forming ten overlapping columns with every card visible. The other 64 cards are the stock.
Build the eight foundations up by suit, from Ace to King. In the columns, build down by suit. Only the top card of a column can be moved, one card at a time, and any single card can go into an empty column.
Turn cards from the stock one at a time onto the waste pile. The top card of the waste can be played to a column or a foundation. You can only go through the stock once.
Forty Thieves is a two-deck patience, and it is said to be the version Napoleon played during his final exile on St Helena. Under the name Napoleon at St. Helena it is recorded as early as 1870, by Annie Henshaw, one of the earliest documented references to the game.
It appears often in the patience collections of the late 19th century. Lady Adelaide Cadogan, writing in 1874, calls it Le Cadran, which suggests a possible French origin. In the 1920s American sources began recording Big Forty and Forty Thieves as alternative names.
It remains one of the most popular two-deck patiences, and it is the ancestor of a large family of similar games, most of them designed to be easier to win.
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