How were balloons invented?

In the second or third century AD, the earliest hot air balloon sky lanterns were invented in China and were used to transmit military signals.
Hot air balloons have a long history in China and are called sky lanterns or Kongming lanterns. The famous scholar Joseph Needham also pointed out that the Mongols used dragon-shaped sky lanterns to transmit signals during the Battle of Liegnitz in 1241 AD. It was only in 1783 that the French Montgolfier brothers released Europe's first balloon filled with hot air. The French Robert brothers were the first to fly into the sky in a hydrogen-filled balloon.
It was the winter of 1772. The Montgolfier brothers in Lyon, France, were sitting in front of the fireplace warming themselves, and a thick smoke rushed up to the top of the stove. As my brother watched, an interesting idea suddenly came to his mind: If I made a bag and put cigarettes in it, wouldn't it make the bag fly? So the two brothers found silk, sewed it into a bag, and then filled the bag with cigarettes. The bag really rose - this was the earliest balloon that appeared in mankind.
Later, after 10 years of hard work, the Montgolfier brothers finally sent a huge hot air balloon into the sky in 1783. When the king found out, he specially invited them to perform at Versailles Palace.