Complex sentence: According to the "Samguk Sagi", she was the first of Jinpyeong of Silla's daughters, but according to other historical records, she was the second of King Jinpyeong's daughters and much younger than her elder sister, Princess Cheonmyeong.
Split into simpler sentences: According to the Samguk Sagi, she was the first of King Jinpyeong's daughters. But according to other historical records, she was the second of King Jinpyeong's daughters and much younger than her elder sister, Princess Cheonmyeong.