By posing a rabbit-breeding puzzle in his 1202 book Liber Abaci
The sequence was already known in India (described by Pingala, Virahanka, and Hemachandra centuries earlier), but Fibonacci popularized it in Europe with a puzzle: starting from one pair of rabbits that produces a new pair each month, how many pairs exist after a year? The monthly totals run 1, 1, 2, 3, 5, 8, 13...
