Captioned: "Court chariot of Assurbanipal with ten-spoked wheels." Ashurbanipal also spelled Assurbanipal or Ashshurbanipal, was an Assyrian king, the son of Esarhaddon and the last strong king of the Neo-Assyrian Empire. He is famed for amassing a significant collection of cuneiform documents for his royal palace at Nineveh The invention of the wheel falls in the late Neolithic, and may be seen in conjunction with other technological advances that gave rise to the early Bronze Age. Evidence of wheeled vehicles appears from the second half of the 4th millennium BC, in Mesopotamia (Sumerian civilization), the Northern Caucasus (Maykop culture) and Central Europe, so that the question of which culture originally invented the wheeled vehicle is still unsolved. Early wheels were simple wooden disks with a hole for the axle. Because of the structure of wood, a horizontal slice of a tree trunk is not suitable, as it does not have the structural strength to support relevant stresses without failing; rounded pieces of longitudinal boards are required. The invention of the wheel has also been important for technology in general, important applications including the water wheel, the cogwheel, the spinning wheel, and the astrolabe.