<P> Later Silla was a golden age of art and culture . During this period, long - distance trade between Later Silla and the Abbasid Caliphate was documented by Persian geographer Ibn Khordadbeh in the Book of Roads and Kingdoms . Buddhist monasteries such as the World Heritage Sites Bulguksa temple and Seokguram Grotto are examples of advanced Korean architecture and Buddhist influence . Other state - sponsored art and architecture from this period include Hwangnyongsa Temple and Bunhwangsa Temple . Persian chronics described Silla as located at the eastern end of China and reads' In this beautiful country Silla, there is much gold, majestetic cities and hardworking people . Their culture is comparable with Persia' . </P> <P> Later Silla carried on the maritime prowess of Baekje, which acted like the Phoenicia of medieval East Asia, and during the 8th and 9th centuries dominated the seas of East Asia and the trade between China, Korea and Japan, most notably during the time of Jang Bogo; in addition, Silla people made overseas communities in China on the Shandong Peninsula and the mouth of the Yangtze River . Later Silla was a prosperous and wealthy country, and its metropolitan capital of Gyeongju was the fourth largest city in the world . </P> <P> Buddhism flourished during this time, and many Korean Buddhists gained great fame among Chinese Buddhists and contributed to Chinese Buddhism, including: Woncheuk, Wonhyo, Uisang, Musang, and Kim Gyo - gak, a Silla prince whose influence made Mount Jiuhua one of the Four Sacred Mountains of Chinese Buddhism . </P> <P> Silla began to experience political troubles in late 8th century . This severely weakened Silla and soon thereafter, descendants of the former Baekje established Hubaekje . In the north, rebels revived Goguryeo, beginning the Later Three Kingdoms period . </P>

When was the last time korea was unified