Alexander the Great's diving bell. 15th-century manuscript illustration of the 4th-century BC ruler Alexander the Great (356 BC-323 BC) being lowered into the sea in a glass barrel, an early form of diving bell. Alexander, from Macedon, become emperor of most of the known world. He was a student of the Ancient Greek philosopher Aristotle who mentions diving bells, and Alexander is said to have used them in the siege of Tyre in 332 BC. Such stories were re-told in the Middle Ages in a tradition called the Alexander romances. This illustration is from a French translation known as the Shrewsbury Talbot Book of Romances, produced in Rouen prior to 1445.