What was the name of Korea before Korea?

It was called Gojoseon until 1897 when it became Korea. It was under Japanese rule from 1910 to 1945 and split into North and South Korea in 1948.

No, Gojoseon was founded in 2333 BC and lasted until 108 BC. Then came the Proto-Three Kingdoms era, then the Three Kingdoms, then Unified Silla & Balhae, then was split into 3 again, then came GORYEO (where the present day English name Korea comes from), then Joseon, then the Korean Empire, then the Japanese rule, Allied invasion of colonized Korea, and then finally the present day North & South Korea.