At the rate of one woman per night, that would take 13.7 years.
“In 281, Emperor Wu took 5,000 women from Sun Hao’s palace into his own, and thereafter became even more concentrated on feasting and enjoying the women, rather than on important matters of state. It was said that there were so many beautiful women in the palace that he did not know whom he should have sexual relations with; he therefore rode on a small cart drawn by goats, and wherever the goats would stop, he would stop there, as well. Because of this, many of the women planted bamboo leaves and salt outside their bedrooms — both items said to be favored by goats.” (More at Wikipedia)
Related: “Audacious historical cause-and-effect claims” (e.g., J.S. Mill’s claim about the Battle of Marathon.