Guillaume Apollinaire
Two years after being wounded in World War I, Apollinaire died in the Spanish flu pandemic of 1918; he was 38.
Guillaume de l'Hôpital
Guillaume François Antoine, Marquis de l'Hôpital (; 1661 – 2 February 1704) 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. Several editions and translations to other languages were published and it became a model for subsequent treatments of calculus.