Many children bring happiness, starting from marrying a wife and starting to dominate the world

Lu Chen traveled to the Great Xia Dynasty and became the ninth prince of the Great Xia Dynasty.
Unlike the time-travelers in the novel, Lu Chen does not have extensive knowledge of science and engineering, nor can he remember many ancient poems.
In order not to get involved in the fight for the legitimate heir, Lu Chen had no choice but to lie down and plan to live a peaceful life enjoying the glory and wealth.
Because of his status as mother and concubine, Lu Chen was eventually granted a marriage by the emperor, and was entrusted to the bitter cold land in the north to become a prince.
Just when Lu Chen thought he was going to fall like this for the rest of his life, the system was activated on his wedding night.
As long as a child is born, Lu Chen will be able to receive rewards and improve his own strength.
Years later.
Lu Chen led a million-strong army to King Qin of Beijing, and everyone was shocked.
"Isn't this guy a useless prince? He has an army of millions!"
"Under what circumstances can he still be a great master?"
"It turns out that the Ninth Prince's fall was all staged!"
…