Question: Princess Cheonmyeong, was a princess of Silla, one of the Three Kingdoms of Korea, and is notable as the sister of Queen Seondeok of Silla, and reigned as Silla's which number ruler?
Sentence (from "Queen Seondeok of Silla"): Queen Seondeok of Silla (Hangul: 선덕여왕 ] ; 595~610 – 17 February 647) reigned as Queen Regnant of Silla, one of the Three Kingdoms of Korea, from 632 to 647.
Relevant evidence: Yes