Answer:
The Three Kingdoms Period of ancient Korea (57 BCE – 668 CE) is so-called because it was dominated by the three kingdoms of Baekje (Paekche), Goguryeo (Koguryo), and Silla.
Explanation:
https://www.worldhistory.org/Three_Kingdoms_Period_in_Korea/#:~:text=The%20Three%20Kingdoms%20Period%20of,(Koguryo)%2C%20and%20Silla.
Hope this helps.
