The balloon was a product of the scientific revolution of the 17th and 18th centuries. Early modern experimenters like the Englishman Robert Boyle, studied the physics of the atmosphere. By the 18th century the focus shifted to the discovery of the constituent gases that make up the atmosphere. Early plans for flying machines inspired by the new discoveries were impractical, but quickly gave way to the first real balloons.

In 1670, Francesco Lana de Terzi (1631-1687), inspired by recent discoveries in the physics of gases, suggested constructing a flying machine featuring four metal globes that would be evacuated of air and thus, perhaps, light enough to make the craft buoyant. The craft was never constructed and was beyond the technology of the period. This image appeared as an illustration in a 1789 issue of The European Magazine. Engraving, English, 1789

This is a fanciful flying ship proposed by the Brazilian Jesuit Bartolomeu de Gusmão (1685–1724). Gusmão is said to have flown a small balloon before the Portuguese court in Lisbon’s Casa da India on August 8, 1709. Etching from a publication, English, 18th century
Humankind first took to the sky using the principle of buoyancy. As the Greek philosopher Archimedes explained, when an object weighs less than the amount of fluid it displaces, it will rise until it reaches an equilibrium point. A balloon can become buoyant when filled with hot air or a gas that is lighter than air, such as hydrogen. While small hot air balloons were flown centuries ago in Asia, and a small balloon may have been flown in Lisbon as early as 1704, the first people did not venture aloft until the fall and winter of 1783.
The brothers Joseph-Michel Montgolfier (1740–1810) and Jacques-Étienne Montgolfier (1745–1799), papermakers from Annonay, France, launched the era of spectacular hot air balloon flights. On June 4, 1783, the Montgolfier’s sent a small hot air balloon aloft from the public square of their hometown of Annonay, France. News of the flight spread slowly across France, generating curiosity and excitement.

This uncolored etching depicts the profiles of the Montgolfier brothers based on a commemorative medal.

This aquatint, a print meant to resemble a watercolor painting, depicts a hot air balloon ascending over a village. Aquatint, Possibly French, 18th century
Inspired by reports of the Montgolfier flight, Parisians commissioned chemical experimenter Jacques Alexandre César Charles (1746–1823) to provide a balloon demonstration for the capital. Charles filled his balloon with the lightweight hydrogen, rather than hot air. He sent his first small gas balloon aloft from the Champ de Mars on August 27, 1783. In the below hand-colored etching you can see a chest in the foreground. The chest contained dilute sulfuric acid and metal filings used to generate hydrogen to fill the balloon.
Charles’ balloon landed in the village of Gonesse that afternoon, some 16 kilometers (10 miles) from the launch point. It was attacked by local peasants who assumed it was a demon that had fallen from the sky.