Which Montgolfier brother was the elder inventor of the 1783 hot-air balloon?

Joseph-Michel Montgolfier was the elder inventor of the 1783 hot-air balloon.

Joseph-Michel was born in 1740, three years before his younger brother Étienne. The brothers became interested in buoyant flight while working with paper and air in their family’s paper-making business in Annonay, France.

Their early experiments led to the public demonstration of an unmanned balloon in June 1783. Étienne later became especially prominent in the balloon’s construction and promotion, which can sometimes cause sources to mention him first. However, Joseph-Michel was the elder brother and an important originator of the experiments.

The Montgolfiers’ balloon did not rely on hydrogen. It rose because heated air inside the paper-and-fabric envelope was less dense than the surrounding atmosphere. Their work helped begin the era of practical human balloon flight.