The Battle of Gangut (, , Finland Swedish:Slaget vid Rilax, ) took place on 27 JulyJul./ 7 August 1714Greg. during the Great Northern War (1700–21), in the waters of Riilahti Bay, north of the Hanko Peninsula, near the site of the modern-day city of Hanko, Finland, between the Swedish Navy and Imperial Russian Navy. It was the first important victory of the Russian fleet in its history.