Complex sentence: Hwang Yun-gil, also known as Hwang Yun'gil, was a Korean diplomat and ambassador, representing Joseon interests in a "tongsinsa" (diplomatic mission or corresponding envoys) to Sengoku period in Japan when it was constrolled by strongman Toyotomi Hideyoshi.
Split into simpler sentences: Hwang Yun-gil, also known as Hwang Yun'gil, was a Korean diplomat and ambassador. He represented Joseon interests in a "tongsinsa" (diplomatic mission or corresponding envoys) to Sengoku period in Japan when it was controlled by strongman Toyotomi Hideyoshi.