Guillaume de L'Hôpital, marquis de L'Hôpital

He is said to have been related to Michel de L'Hôpital, Chancellor of France, but the heraldry of the two families suggests there was no relationship.

http://fr.wikipedia.org/wiki/Guillaume_Fran%C3%A7ois_Antoine,_marqu...

For information on his coat of arms, including the family's purported connection to the royal family of Naples, see http://www.numericana.com/arms/lhospital.htm.

Wikipedia Biographical Summary:

"...Guillaume François Antoine, Marquis de l'Hôpital[ (?, 1661, Paris – 2 February 1704, Paris) was a French mathematician. His name is firmly associated with l'Hôpital's rule for calculating limits involving indeterminate forms 0/0 and ∞/∞. Although the rule did not originate with l'Hôpital, it appeared in print for the first time in his treatise on the infinitesimal calculus, entitled Analyse des Infiniment Petits pour l'Intelligence des Lignes Courbes. This book was a first systematic exposition of differential calculus.

L'Hôpital was born into a military family. His father was Anne-Alexandre de l'Hôpital, a Lieutenant-General of the King's army, Comte de Sainte-Mesme and the first squire of Gaston, Duke of Orléans. His mother was Elisabeth Gobelin, a daughter of Claude Gobelin, Intendant in the King's Army and Councilor of the State..."

SOURCE: http://en.wikipedia.org/wiki/Guillaume_de_l%27H%C3%B4pital