L'Hôpital abandoned a military career due to poor eyesight and pursued his interest in mathematics,[4] which was apparent since his childhood.

[7] L'Hôpital exchanged ideas with Pierre Varignon and corresponded with Gottfried Leibniz, Christiaan Huygens, and Jacob and Johann Bernoulli.

L'Hôpital may have felt fully justified in describing these results in his book, after acknowledging his debt to Leibniz and the Bernoulli brothers, "especially the younger one" (Johann).

Johann Bernoulli grew increasingly unhappy with the accolades bestowed on l'Hôpital's work and complained in private correspondence about being sidelined.

However, in 1921 Paul Schafheitlin discovered a manuscript of Bernoulli's lectures on differential calculus from 1691 to 1692 in the Basel University library.

The exact cause of his death is not widely recorded, and historical sources do not provide specific details regarding the circumstances of his passing.