Crete entered upon the purely Greek period of its history with the arrival of massive waves of Dorians, about 1100 BC. The Protogeometric period that followed (1100-900 BC) unfolded alongside the Sub-Minoan, for the earlier Cretan cultural tradition continued to offer resistance in certain areas, particularly in central and eastern Crete. No one today doubts the contribution made by the Minoan and Mycenean empire to the creation of the Greek civilisation. The use of iron, and cremation of the dead became general, and the urns for the ashes are amongst the most characteristic vessels of the period.