Original: European maps continued to show this hypothetical land until Captain James Cook's ships, HMS Resolution and Adventure, crossed the Antarctic Circle on 17 January 1773, in December 1773 and again in January 1774.
Simplified: European maps continued to show this unknown land until Captain James Cook's ships, HMS Resolution and Adventure, crossed the Antarctic Circle on 17 January 1773, in December 1773. They crossed it again in January 1774.