Kammala wannan jumla: A shekara ta 936, Wang Geon, zuriyar Goguryeo, wanda ya kafa Goryeo a matsayin magajin Goguryeo, ya haɗa Masarautu Uku na Ƙarshe. Balhae ya faɗi ga Daular Khitan a 926, kuma shekaru goma bayan haka, ɗan sarki na ƙarshe na Balhae ya tsere zuwa kudu zuwa Goryeo, inda Wang Geon ya yi maraba da shi sosai kuma ya haɗa shi cikin dangin mai mulki, don haka ya haɗa al'ummomin biyu na Goguryeo. Kamar Silla, Goryeo ya kasance jihar da ke da al'adu sosai, kuma ya kirkiro matattarar buga takardu ta ƙarfe. Bayan kayar da Daular Khitan, wacce ita ce daular da ta fi karfi a lokacinta, a cikin Goryeo <unk> Khitan War, Goryeo ya sami lokacin zinariya wanda ya ɗauki ƙarni, wanda aka kammala Tripitaka Koreana kuma akwai manyan ci gaba a cikin bugawa da bugawa, inganta ilmantarwa da watsa ilimi kan falsafa, adabi, addini, da kimiyya; a shekara ta 1100, akwai jami'o'i 12 da suka samar da shahararrun malamai da masana kimiyya. Duk da haka, da
Mamayewar Mongol a ƙarni na 13 ya raunana masarautar sosai. Mongols ba su taɓa cin Goryeo ba, amma sun gaji bayan shekaru talatin na yaƙi, kotun Koriya ta aika da yarima mai jiran gado zuwa babban birnin Yuan don yin rantsuwa ga Kublai Khan, wanda ya karɓa, kuma ya auri ɗaya daga cikin 'ya'yansa mata ga yarima mai jiran gado na Koriya. Daga nan, Goryeo ya ci gaba da mulkin Koriya, kodayake a matsayin abokin haɗin gwiwa ga Mongols na shekaru 86 masu zuwa. A wannan lokacin, al'ummomin biyu sun haɗu da juna kamar yadda duk sarakunan Koriya da suka biyo baya suka auri 'yan matan Mongol, kuma sarauniyar karshe ta daular Yuan ita ce yarinyar Koriya. A tsakiyar karni na 14, Goryeo ya kori 'yan Mongol don sake dawo da yankunan arewacinsa, ya yi nasara a Liaoyang, kuma ya ci nasara da mamayewar Red Turbans. Amma, a shekara ta 1392, Janar Yi Seong-gye, wanda aka ba shi umurni ya kai wa ƙasar Sin hari, ya juya sojojinsa kuma ya yi juyin mulki.