According to Samguk Yusa, his third daughter Princess Seonhwa, married King Mu of Baekje. (Historians considered this unlikely, given the hostilities between the rival kingdoms.) Since King Jinpyeong was only 13 years old when he ascended the throne, Queen Dowager Sado, had to serve as a Regent until he reach the legal age. However, Queen Sado still refused to give him full control of Silla even after he reached the legal age. She appointed "Noribu", as the Sangdaedeung and "Hujik" as the head of the Military. Noribu died on December of 588, "Sueulbu" became the next Sangdaedeung after him. King Jinpyeong relied heavily on these two chief officials to solidify his kingdom in both internal affairs and international relations. He also gave the rank of "Galmunwang" to his brothers Baekban and Gukban, to solidify his power in the court. King Jinpyeong's achievement was the way he strengthened the Kingdom and improved the political system. He named himself, his wife and his younger siblings as people related to the Buddha which eventually made the entire royal family being seen as a especial household for the throne, completely different compared to the rest of the royal nobles. He also built different departments for different political purposes, such as: The Ministry of Culture and Tourism and the Ministry of Education. Buddhism was embraced during this era, as King Jinpyeong actively sent envoys and monks to China to study and help in diplomatic relations. Buddhism in Silla developed as a strong, nation-protecting religion. Year 594, King Jinpyeong sent a diplomat to Sui dynasty of China in order to establish a diplomatic relationship between their countries. Two years later, he sent Monk Damyook to Sui in order to study Chinese Buddhism. Year 602, Amak Fortress was invaded by Baekje forces led by General Hae Su. As a result, King Jinpyeong sent thousands of soldiers to fight them back and built fortresses in Cheonsan, Sota and Wae Seok. However, King Mu of Baekje fought back by sending 40,000 troops to attack the said fortresses. Silla sent General Gunpoom and Mu Eun to fight them back. During the battle, Mu Eun fell into Hae Su's ambush and almost got killed but was saved by his son Gwisan and Chu Hang, however the two were both killed in the battle.