The Furnace of the Korean Peninsula - The Three Kingdoms Period

The Three Kingdom’s period refers to the time between the 1st century BCE until the 7th Century CE on the Korean peninsula and extending into Manchuria (in present-day China and Russia). At the beginning of this period, the southern part of the peninsula was occupied by tens of local city-states organized into three confederacies: Mahan (southwest), Jinhan (southeast), and Byeonhan (mid-south), collectively referred to as the Samhan (lit. “three han”). Meanwhile, in the northern part of the peninsula and extending into Manchuria were various kingdoms, including Buyeo (far north), Okjeo (far northeast), Dongye (mid-east), and Goguryeo (north). By the 4th century CE, as local city-states consolidated power in each region, Mahan, Jinhan, and Byeonhan would develop into the kingdoms of Baekje, Silla and Gaya, respectively, while northern kingdoms were consolidated by Goguryeo. It was around this time that Buddhism was introduced to the peninsula, becoming the official religion of the kingdoms. By the end of the 5th century, Goguryeo extended far into Manchuria and left only the southern-most regions of the peninsula to Baekje, Gaya, and Silla. In the mid-6th century, Silla fully conquered Gaya and made territorial gains in the Hangang River basin at the expense of Goguryeo. After further territorial struggles between Goguryeo, Baekje, and Silla (the three kingdoms from which the period gets its name) from the late 6th until the mid-7th century, Silla was able to weaken Baekje and Goguryeo through an alliance with Tang China and consolidated the southern two-thirds of the peninsula into what is known as Unified Silla in 676. Information on these periods can be found in the History of the Three Kingdoms and Memorabilia of the Three Kingdoms, from the 12th and 13th centuries, respectively.

Five-Story Stone Pagoda of Jeongnimsa Temple, built during Baekje (National Treasure No. 9; Dongnam-ni, Buyeo-eup, Buyeo-gun, Chungcheongnam-do)
Cheomseongdae Observatory, an astronomical observatory built in Silla at the end of the Three Kingdoms period by Queen Seondeok (National Treasure No. 31; Gyeongju, Gyeongsangbuk-do).
Achasanseong Fortress from the Goguryeo period (Gwangjang-dong, Gwangjin-gu, Seoul)