Maritime archaeology, the first of these sub-disciplines to emerge in Australia, commenced under the aegis of Jeremy Green in the 1970s after concerns were expressed by academics and politicians over the rampant destruction of Dutch and British East Indian ships lost on the west coast. After Commonwealth legislation was enacted and enforced after 1976 and the states enacted their own legislation, the sub-discipline spread throughout Australia, as a result of on-going funding by both the states and the Commonwealth. While also encompassing the study of port-related structures (e.g. jetties, anchorages), lighthouses, moorings, defences etc., initially the focus in maritime archaeology was solely on shipwrecks.