Lufia: The Ruins of Lore, known in Japan as Chinmoku no Iseki: Estpolis Gaiden (沈黙の遺跡 ～エストポリス外伝～), is a role-playing video game developed by Atelier Double and published by Taito in Japan in 2002 and by Atlus a year later in North America. It is the fourth title in the Lufia series of video games and was released as a "gaiden", or side story, to the main series; as a result, it does not feature many elements common to the rest of the series, such as the Sinistrals and the Dual Blade.