Michel de L'Hôpital was a French mathematician born in 1696, best known for his work in calculus. He is particularly recognized for L'Hôpital's Rule, which provides a method for finding limits of indeterminate forms. This rule is widely used in mathematics, especially in calculus courses. L'Hôpital studied under the famous mathematician Johann Bernoulli and published his influential book, "Analyse des Infiniment Petits," in 1696. His contributions helped lay the groundwork for future developments in calculus and analysis, making him an important figure in the history of mathematics.