to 70 cm range. Robert Drews linked the Naue Type II Swords, which spread from Southern Europe into the Mediterranean, with the Bronze Age collapse. Naue II swords, along with Nordic full-hilted swords, were made with functionality and aesthetics in mind. The hilts of these swords were beautifully crafted and often contained false rivets in order to make the sword more visually appealing. Swords coming from northern Denmark and northern Germany usually contained three or more fake rivets in the hilt. Sword production in China is attested from the Bronze Age Shang dynasty. The technology for bronze swords reached its high point during the Warring States period and Qin dynasty. Amongst the Warring States period swords, some unique technologies were used, such as casting high tin edges over softer, lower tin cores, or the application of diamond shaped patterns on the blade (see sword of Goujian). Also unique for Chinese bronzes is the consistent use of high tin bronze (17–21% tin) which is very hard and breaks if stressed too far, whereas other cultures preferred lower tin bronze (usually 10%), which bends if stressed too far. Although iron swords were made alongside bronze, it was not until the early Han period that iron completely replaced bronze. In the Indian subcontinent, earliest available Bronze age swords of copper were discovered in the Indus Valley civilization sites in the northwestern regions of South Asia. Swords have been recovered in archaeological findings throughout the Ganges-Jamuna Doab region of Indian subcontinent, consisting of bronze but more commonly copper. Diverse specimens have been discovered in Fatehgarh, where there are several varieties of hilt. These swords have been variously dated to times between 1700 and 1400 BC. Other swords from this period in India have been discovered from Kallur, Raichur. Iron Age Iron became increasingly common from the 13th century BC. Before that the use of swords was less frequent. The iron was not quench-hardened although often containing sufficient carbon, but work-hardened like bronze by hammering. This made them comparable or only slightly better in terms of strength and hardness to bronze swords. They could still bend during use rather than spring back into shape. But the easier production, and the better availability of the raw material for the first time permitted the equipping of entire armies with metal weapons, though Bronze Age Egyptian armies were sometimes fully equipped with bronze weapons. Ancient swords are often