Short answers, pulled from the story.
Yuan dynasty troops are recorded to have used hand cannons in combat against rebel forces led by Prince Nayan in 1288. The earliest extant cannon bearing a date of production is the Xanadu Gun, dated to 1298.
The word cannon derives from the Old Italian term meaning large tube, which itself traces back to the Latin and Greek words for reed. This linguistic lineage suggests that early observers saw these new weapons as simply hollow tubes, much like a plant stem.
By 1453, Ottoman forces used 68 Hungarian-made cannons to breach the walls of Constantinople after a 55-day bombardment. The largest of these, the Great Turkish Bombard, required an operating crew of 200 men and 70 oxen.
On the 5th of October 1795, Napoleon ordered his cannon to fire grapeshot into the mob during the assault on Paris known as the whiff of grapeshot. This act effectively ended the threat to the new government while making Bonaparte a famous public figure.
William Armstrong invented the breech-loading Armstrong Gun in the mid-19th century boasting improved range and power. Rifling casting spiraling lines inside the barrel gave projectiles gyroscopic stability improving accuracy significantly by 1855.