Vasa, Kronan and Mars are the most famous Swedish warships, and well-researched shipwrecks. But they are only a few of a unique range of early-modern naval ships, most of which were purposely sunken in order to fill in and extend quays in port areas across Sweden. These “lost” ships, largely undocumented and unexplored, form a central part of Sweden’s yet unwritten maritime past. The multidisciplinary research program “The Lost Nayv: Sweden’s ‘Blue’ Heritage c. 1450-1850” aims to explore, describe, and research this world of unique shipwreck material—compromising the entire range of sunken vessels from the sailing navy—from the perspectives of maritime archaeology, history, ethnology, and heritage studies. The research will draw on a combination of known but unexplored sources, including documents and artefacts from archives and museum collections as well as new and old archaeological findings, employing a novel “life cycle” perspective of ships concerned. While based at the multidisciplinary Centre for Maritime Studies (CEMAS), at Stockholm University the project will develop deep ties with Swedish Maritime and Transport Museums (SMTM).