The Princess Who Traveled Through a Subjugated Country Became a Queen

Ancient Sayings, Time Travel, Short

It is a modern person who travels to ancient times (alternative history) and becomes a three-year-old child with two older brothers. His father is a high-ranking official and his wife is a beautiful woman who is the favorite of the group. I have played well with the princess and prince since I was a child. Halfway through, I forgot to add it to the bookshelf and it disappeared. Please help. The male protagonist seems to be named Mo