Sir Alexander Fleming was born in Darvel, East Ayrshire, Scotland, on 6 August 1881 and he is best known for having discovered penicillin, which is still used to treat bacterial infections today.
He moved to London at the age of 13 and later trained as a doctor. He qualified with distinction in 1906 and began research at St Mary's Hospital Medical School at the University of London under Sir Almroth Wright, a pioneer in vaccine therapy.
In 1928, while studying the influenza virus, Fleming noticed that mould had developed accidentally on a set of dishes being used to grow the staphylococci germ. The mould had created a bacteria-free circle around itself. Fleming experimented further and named the active substance penicillin. This discovery would change the world of medicine forever and cement Fleming's place as one of the world's most famous scientists. In 1944, Fleming was knighted by King George VI and won the Nobel Prize a year later.