Irena Sendler (1910-2008) saved around 2,500 Jewish children from the Warsaw ghetto in the Second World War. Despite being captured and tortured by the Gestapo, she never revealed the identities of the children (who are now grown and living full lives) or her accomplices. She escaped after one of her guards was bribed, and was later nominated for a Nobel Peace Prize.
Rosalind Franklin is arguably the most important woman in science ever, yet most of us have never heard her name. She was a key player in the team that unravelled DNA, the team that won a Nobel Peace Prize for it in 1962 - but Rosalind had died in 1958, aged just 37, after battling ovarian cancer. The NPP is never awardes posthumously, so Rosalind went entirely unacknowledged until 1968, when her colleagues publicly recognised her hard work.
Murasaki Shikubu (c.978-1030 approx) wrote The Tale of Genji, which some say was the first great novel, and others say was the first novel, period. She wrote it (basically inventing the art form of the novel) after her husband died, leaving her a single parent. Tragically, due to her time, very little is known about her, but her novel survives as a literary masterpiece.
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