<P> Contrary to popular belief, some Mycenaean representative buildings already featured roofs made of fired tiles, as in Gla and Midea . </P> <P> The military nature of the Mycenaean Greeks is evident from the numerous weapons unearthed, the use of warrior and combat representations in contemporary art, and the preserved Greek Linear B records . The Mycenaeans invested in the development of military infrastructure, with military production and logistics being supervised directly from the palatial centers . According to the Linear B records in the palace of Pylos, every rural community (the damos) was obliged to supply a certain number of men who had to serve in the army . Similar service was also performed by the aristocracy . </P> <P> Mycenaean armies were initially based on heavy infantry, equipped with spears, large shields and in some occasion armor . Later in the 13th century BC, Mycenaean warfare underwent major changes both in tactics and weaponry and armed units became more uniform and flexible, while weapons became smaller and lighter . The spear remained the main weapon among Mycenaean warriors, while the sword played a secondary role in combat . Other offensive weapons used were bows, maces, axes, slings and javelins . The precise role and contribution of chariots on the battlefield is a matter of dispute due to the lack of sufficient evidence . It appears that chariots were initially used as fighting vehicles during the 16th to 14th centuries BC, while later, in the 13th century BC, their role was limited to battlefield transport . </P> <P> The boar's tusk helmet was the most identifiable piece of Mycenaean armor in use from the beginning to the collapse of Mycenaean culture . It is also known from several depictions in contemporary art in Greece and the Mediterranean . A representative piece of Mycenaean armor is the Dendra panoply (c. 1450--1400 BC) which consisted of a cuirass of a complete set of armor made up of several elements of bronze . In general, most features of the later hoplite panoply of classical Greek antiquity, were already known to Mycenaean Greece . "Figure - of - eight" shields were the most common type of Mycenaean shields . During the Late Mycenaean period, smaller types of shields were adopted, either of completely circular shape, or almost circular with a part cut out from their lower edge . </P>

Who were the invaders that helped contribute to the collapse of mycenae