Diades of Pella

Engineer, Inventor (4^th century BC)

Diades the Besieger, also known as Diades of Pella, was Alexander’s engineer in his expedition in Asia. Together with Charias they constructed some of the most impressive and powerful war machines used by Alexander’s army in his conquests, which proved decisive in his victories against the Persians. He chiefly designed battering rams, moving towers, catapults and cranes aimed at demolishing enemy walls.

Nothing is known about Diades, save for his inventions. These include the following:

• The “Moving Towers” was a siege engine made of towers that could be disassembled and reassembled on site by the warriors. They were used to siege cities.
• The “palintonos” catapult, a V-spring catapult that launched stones at distance.
• The demolition raven, a tall scaffold with wheels. It had a long beam extending on both sides, one of which was operated by the operators on the back, and the front one, which resembled a raven’s beak and was used to extract rocks from the enemy’s walls. This way, it could demolish walls of cities.
• The Wall Perforator, a sophisticated siege engine used for perforating walls.
• The lifting machine, which was used for helping warriors climb on walls. It resembled the climax of Magirus.
• The ditch-filling tortoise was an armoured, pyramid-shaped vehicle that literally resembled a turtle. It was used in sieges for the levelling of ground and for filling the defensive ditches around cities. This way, it was easier for war machines to approach their target. Its area spanned 120 square meters for the protection of the digging crew that hid under it. Its exposed walls were covered with iron sheets, wicker wood, clay mixed with hair and lambskins stuffed with seaweed soaked with vinegar in order to neutralize incoming fire arrows and to absorb the impact of stones. The machine could move in all directions. Another version of the machine, the digging tortoise, had a vertical front face, enabling better contact with the wall and a greater efficacy.
• The trypanon, or borer, was a war machine resembling an oversized drill, operated by warriors inside a platform, covered by a double-layered roof. The drill consisted of a wooden beam with a metal head at its tip, fastened with ropes that ran around a series of pulleys. By moving the ropes, the beam moved backward and forward, able to jam the enemy wall.
• The roofed ram, a cage on wheels with a double-layered roof and a three-storey tower equipped with catapults. Its lower storeys were used for water reservoir in case of fire. On its floor, there were a series of holders on which the battering ram moved. The operators on both sides moved the ram by pulling the ropes, causing it to strike the enemy wall with great force.
• The epivathra was a type of movable bridge that was used not only for bypassing enemy walls but also during sea battles.

Diades was also responsible for developing and improving some of the older war engines used by Philipp II, most notably the euthytonos catapult, or the scorpion, was it was called, which could launch arrows at a long range. He wrote a treatise on engineering and the descriptions of his machines have survived in Heron’s works.

Bibliography:

1. Georgakopoulos, Konstantinos. Ancient Greek Scientists. Georgiades, Athens: 1995. Print.
2. Kotsanas, Kostas. Ancient Greek Technology The Inventions of the Ancient Greeks. Kostas Kotsanas: Pyrgos, 2013. Print.