The 84-year-old Argentinian has previously had to cancel several events due to his battles with nerve pain condition Sciatica. But at the weekend, Pope Francis surprised Edith Bruck, an 89-year-old Hungarian-born Holocaust survivor and author, at her home in Rome.
The pope paid tribute to all those killed by Nazi “insanity”.
Ms Bruck was born into a poor Jewish family and spent time in a number of concentration camps.
She tragically lost her father, mother and brother in the camps.
A Vatican spokesman said Pope Francis spoke to Ms Buck about her time in the camps and the importance of future generations learning about the Holocaust.
The spokesman quoted the pope saying: “I came here to thank you for your witness and to pay homage to the people martyred by the insanity of Nazi populism.”
Ms Bruck was about 13 when she was taken to Auschwitz in German-occupied Poland with her family.
After spending time in a series of concentration camps, Ms Bruck ended up in Bergen-Belsen, where she was liberated by the Allies in 1945.
The Nazis and their allies murdered around six million Jews in German-occupied Europe.
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The pope skipped several Masses in January due to a bout with the chronic condition that causes pain in his hips.
In 2013, Pope Francis told reporters he had suffered a burst of sciatica after being elected head of the Catholic Church earlier that year.
He said: “The worst thing that happened, excuse me, was an attack of sciatica, really, that I had the first month, because I was sitting in an armchair to do interviews and it hurt.
“Sciatica is very painful, very painful. I don’t wish it on anyone.”
As a result of his condition, the pope walks with a slight limp.
In March, Pope Francis is expected to visit Iraq which would mark the first trip by a pope to the country.