Palace of Desire is one of the best palace dramas I've seen, with quite humane portrayal of Wu Zetian, her daughter Princess Taiping and many other renowned historical figures surrounding them and the struggles of life and politics surrounding them, with a dash of slice of life vibe. Empress of China is comparatively more extravagant, over the top and "dog bloody", filled with harem shenanigans, but if you enjoyed that one, definitely give Palace of Desire a try. This one shouldn't be missed especially if you are interested in Empress Wu Zetian and her legendary life.
