Legend of Ace (2016)

It has Main Character from 20th Century going in the Past. Using his Knowledge of Future to Earn Reputation and Money in Past

Similarities :
The story is based on Time Travel.....
They have Power struggle between royals...
Main lead travel from modern day to historical era.....
Both have parallel world

both the dramas based time-slip/time-travel concepts where male lead travels to past and falls in love with female leads

in both dramas main lead travels back to past
where legend of ace is more comical version and main lead is funny