French government made decision of scientific voyage round the world to improve the knowledge of physical geography and science of the ocean for four years, 1785-1789. La Pérouse was nominated as the commander of this voyage and he set sail from Brest on August 1, 1785 with frigates Boussole and Astrolabe. However, he and all his members were disappeared from Botany Bay, Australia in 1788. He made scientific survey in south-eastern part of Korean waters in May 1787, perhaps the first scientific work in this region ever made. He also introduced Ullnung-Do to Europe for the first time as the name of Isle Dagelet.