Tae jo made important policies. First, he insisted that Goryeo should expand its territory to further North. It is because he succeed to Goguryeo (ancient Korean kingdom founded in 37 BC–668) and Goguryeo had the biggest territory in Korean history. So, Tae jo named the dynasty as Goryeo from Goguryeo and tried to take back the territory of Goguryeo. He emphasized the importance of Sukyung area because it is placed in the North part and kept in check Gu Ran (kind of Mongolian) that made an effort to come down to Goryeo. Later, all of these policies contributed to expanding its territory to Apnok River. Also, Tae Jo made the policy which unified all people from different dynasties (Baekje, Silla, Goguryeo, Balhae..). Because of this policy, Goryeo is considered that it accomplished actual unification compared to Silla.