William Murray, 1st Earl of Mansfield was a British barrister, noted for his reform of English law, and became Lord Chief Justice of England and Wales in 1756. He made a couple of rulings that did not abolish slavery but paved the way for slavery to be abolished in England. His nephew, Captain Sir John Lindsay, had an illegitimate child with a slave and left her in the care of his uncle. The child was baptized Dido Elizabeth Belle in 1766 and was raised along with her cousin Elizabeth Finch. What little we know about Belle's life was that she enjoyed the privilege and responsibility of being raised in an aristocratic family and was well educated. She married John Davinier, a Frenchman who worked as a gentleman's steward, and had three children. She died at the age of 42.
With so little known about Belle's life, the movie Belle is a historical fiction inspired by a painting of her and her cousin. As historical fiction, it is a good story about how slavery, prejudice, social status, and the status of women affected people in this time period. The movie concludes with Murray making a ruling on the Zong Masacre, an incident where a slave ship threw 132 slaves overboard.
This is a very richly written story with some very intelligent period dialog. I admire this movie not just for being a good period piece, but a smart one.