Gunpowder? No. Saltpeter was known by the 1st century AD; but saltpeter is not gunpowder. The earliest reference to gunpowder is from the mid-9th century; but

Gunpowder? No. Saltpeter was known by the 1st century AD; but saltpeter is not gunpowder. The earliest reference to gunpowder is from the mid-9th century; but then it was an alchemical curiosity. The earliest reference to using gunpowder is from the mid-11th century. (All according to Wikipedia.)