Who was the world's first female prime minister?

This woman became a Prime Minister of Ceylon and Sri Lanka in 1960 and served in that position for three times! There is no evidence that she was interested in politics until she became really involved into it in 1940 when she married a politician. Nevertheless, she won the election on her own – one could not deny this fact. Thus, she became the world's first female prime minister. She showed herself as a strong personality and, actually, contributed greatly to the process of nationalizing the key sectors of the economy of her country.