Mary Seacole

 was a 19th century Jamaican doctor who founded Spring Hill in Crimea in the 1850s. She moved there out of a desire to help young soldiers during the war.

Biography
Mary was born in Jamaica to Scottish soldier James Grant and doctor mother, Mrs Grant. Widowed at a young age, she opened a hotel in Panama when it was what the Twelfth Doctor described as "the most dangerous and violent place on Earth". After that, she returned to Jamaica, where she heard about the Crimean War, prompting her to travel halfway round the world to Crimea. In 1855, seven months after she had arrived, she encountered the Twelfth Doctor. (AUDIO: The Charge of the Night Brigade)

Albertine claimed to have been taught battlefield surgery by a woman who was taught by Mary Seacole. (AUDIO: Year of the Pig)

Alternate timeline
In an alternate timeline, an alternate Crimean War was fought between the British Army and an army of Sontarans led by Commander Skaak, with Russia and China replaced by Sontar on a British map of the region. In 1855, Mary helped the Thirteenth Doctor fight and defeat them at Sebastopol. (TV: War of the Sontarans)