Which prince is going to marry her?? Also is the prince already married to someone else???

First I thought it was the 3rd prince as he is one the main cast but it was not him for obvious reasons then I thought it is the 5th prince as she was going at his place . But after reading the comments it turn out to be the 4th prince with the least screentime in the show . the issue is I don't know anything about him

 mparthur:

In history, the 4th prince was kind and gentle compared to the 3rd prince.  The fifth prince was already married and loyal to the deceased king so he would always support the Queen.

That's wrong, especially starting by "in history". Sources are not clear, because contradictory, but historians consider now that they were four brothers, not five. Go Na Moo became king as the eldest after their father's death, and when he died, Queen Woo chose the third prince, future King Sansang, instead of Go Bal Gi. 

Definitely not a trustworthy source, especially for Korean history.

Because the screenwriter choose to follow this theory, for the sake of the dramatisation and fictional adaptation of these historical events, I guess. Historians consider they were only four brothers and King Gogukcheon was the eldest, so naturally succeeded his father.

Instead of using wikipedia as a source, anybody can easily find transcriptions of the "Samguk sagi" (an historical record of the Three Kingdoms of Korea: Goguryeo, Baekje, and Silla, written in the 12th century), which is the primary and only sources about characters and events of that time.

But as they changed many things, and invented even more, the drama is quite far from being close to the actual History. It's a very liberal and fictionalised adaptation of these events and historical characters,

Following on discussion in this thread, could someone recommend good books on Korean history (either in English or in Russian)??? Thank you