Ethel Brilliana Harley Tweedie was born in London to a wealthy British family. She was named in honor of a famous 17th-century relative, Brilliana Lady Harley, who during the English Civil War defended her home, Brampton Bryan Castle, during a siege by Royalist troops. Ethel was educated at Queen's College, London, and in Germany. In 1886, she visited Iceland on vacation with her brother Vaughan, her future husband Alexander (Alec) Leslie Tweedie -- whom she married in 1887 -- and three others. She kept a journal of her travels and published it afterwards as her first book, A Girl's Ride in Iceland (1895). After a visit to Norway two years later, she published her second book A Winter Jaunt to Norway: with Accounts of Nansen, Ibsen, Bjornson, Brandes, and Many Others. Besides further travel writing, her works included a biography of her father, George Harley, F.R.S.: The Life of a London Physician (1899), some early 20th century ethnography studies, and articles and short stories published in the London popular press. She was also a photographer, a prolific painter and a watercolorist; she published many of her sketches and paintings and had exhibitions and one-woman shows. She was an advocate of women's rights, women's suffrage, and higher education for women.