of the Chalcolithic (Copper Age) saw the introduction of copper weapons. Organised warfare between early city states was in existence by the mid-5th millennium BC. Excavations at Mersin, Anatolia show the presence of fortifications and soldiers' quarters by 4300 BC. Excavation work undertaken in 2005 and 2006 has shown that Hamoukar was destroyed by warfare by around 3500 BC-—probably the earliest urban warfare attested so far in the archaeological record of the Near East. Continued excavations in 2008 and 2010 expand on that. Archaeological evidence suggests that Proto-Indo-Iranian-speaking Abashevo society was intensely warlike. Mass graves reveal that inter-tribal battles involved hundreds of warriors of both sides. Warfare appears to have been more frequent in the late Abashevo period, and it was in this turbulent environment in which the Sintashta culture emerged. The spread of spoke-wheeled chariots has been closely associated with early Indo-Iranian migrations. The earliest known chariots have been found in Sintashta culture burial sites, and the culture is considered a strong candidate for the origin of the technology, which spread throughout the Old World and played an important role in ancient warfare. Military conquests expanded city states under Egyptian control. Babylonia and later Assyria built empires in Mesopotamia while the Hittite Empire ruled much of Anatolia. Chariots appear in the 20th century BC, and become central to warfare in the Ancient Near East from the 17th century BC. The Hyksos and Kassite invasions mark the transition to the Late Bronze Age. Ahmose I defeated the Hyksos and re-established Egyptian control of Nubia and Canaan, territories again defended by Ramesses II at the Battle of Kadesh, the greatest chariot battle in history. The raids of the Sea Peoples and the renewed disintegration of Egypt in the Third Intermediate Period marks the end of the Bronze Age. The Tollense valley battlefield is the oldest evidence of a large scale battle in Europe. More than 4,000 warriors from Central Europe fought in a battle on the site in the 13th century BC. Mycenaean Greeks (c. 1600-1100 BC) invested in the development of military infrastructure, while military production and logistics were supervised directly from the palatial centers. The most identifiable piece of Mycenaean armor was the boar's tusk helmet. In general, most features of the later hoplite panoply of classical Greek antiquity, were already known to Mycenaean Greece. The Late Bronze Age collapse was a time of widespread societal collapse during the