Karol Wojtyla became Pope John Paul II in 1978, the first non-Italian to head the Catholic Church for 450 years.
He was born in Poland in 1920, and became a priest in 1946 after secretly studying religion during World War Two.
He visited more than 100 countries, travelled the equivalent of 27 times round the world.
He was the third longest serving Pope, after being in the job for more than 26 years, and carried on his public duties right to the end of his life aged 84.
Pope John Paul II in Italy in 1988
He loved sports, and was a keen football goalkeeper and skier in his younger years.
He also wrote lots of poetry, and even toured Poland appearing in Shakespeare and other plays.
Some people think he was too slow to change the Catholic Church, but he was praised for trying to meet as many people as he could.
One and a quarter million people came together in Dublin's Phoenix Park to see him celebrate Mass in 1979, when he became the first Pope to set foot on Irish soil.
He survived two attempts on his life, but towards the end of his years, he suffered bad health.