Complex sentence: Sunjong ruled for just three years and his reign ended with the Japan-Korea Annexation Treaty in August 1910 and the Japanese abolished the Korean Empire, ending 519 years of Korean rule under the same family.
Split into simpler sentences: Sunjong ruled for just three years; his reign ended with the Japan-Korea Annexation Treaty in August 1910. Japan then abolished the Korean Empire, ending 519 years of Korean rule under the same family.