Anne Lister (1791–1840) was a well-off Yorkshire landowner, diarist, mountaineer and traveller. Throughout her life she kept diaries which chronicled the details of her daily life, including her lesbian relationships, her financial concerns, her industrial activities and her work improving Shibden Hall. Her diaries contain more than 4,000,000 words and about a sixth of them—those concerning the intimate details of her romantic and sexual relationships—were written in code. The code, derived from a combination of algebra and Ancient Greek, was deciphered in the 1930s. Lister is often called "the first modern lesbian" for her clear self-knowledge and openly lesbian lifestyle. Called "Fred" by her lover and "Gentleman Jack" by Halifax residents, she suffered from harassment for her sexuality, and recognised her similarity to the Ladies of Llangollen, whom she visited.