Baekje or Paekche (Hangul: 백제; Hanja: 百濟, ) (18 BCE – 660 CE) was a kingdom located in southwest Korea. It was one of the Three Kingdoms of Korea, together with Goguryeo and Silla.
Baekje was founded by Onjo, the third son of Goguryeo's founder Jumong and So Seo-no, at Wiryeseong (present-day southern Seoul). Baekje, like Goguryeo, claimed to succeed Buyeo, a state established in present-day Manchuria around the time of Gojoseon's fall.
Baekje alternately battled and allied with Goguryeo and Silla as the three kingdoms expanded control over the peninsula. At its peak in the 4th century, Baekje controlled most of the western Korean peninsula, as far north as Pyongyang, and may have even held territories in China, such as in Liaoxi, though this is controversial. It became a significant regional sea power, with political and trade relations with China and Japan.
In 660, it was defeated by an alliance of Silla and Chinese Tang Dynasty, submitting to Unified Silla.