Queen In Hyun's Man
mydramalist.com
Kim Boong Do is a scholar who had supported the reinstatement of Queen In Hyun when Jang Hee Bin's schemes resulted in her being deposed and replaced...

I really liked this one. Time travel combining historical and modern. Probably should re-watch it before talking too much about it. (That’s 95% glitchy aging brain and 97% an excuse to re-watch it :D )