Leonardo Pisano, aka Fibonacci, was an Italian mathematician who popularized the Hindu-Arabic numeral system in the Western World.
He also introduced Europe to the sequence of Fibonacci numbers, which he used as an example in his book in 1202 called Liber Abaci.

Higgledy-Piggledy
Book about abaci,
Treatise on problems that
Math scholars quote,
Gave us a sequence that
Post-Fibonaccian
Pundits still utilize
And on which dote.