Vatican City, about 100 acres in size, was separated from Italy by a Concordat made between Pius XI and Mussolini who was dictator of Italy at the time. I think the year was 1938.
Pius XII was anti-Hitler, but Hitler was the kind of guy that went on killing rampages when he was publicly crossed. One example was when the Dutch Bishops protested the round up of Jews in Holland, the Nazi’s were ordered to intensify their efforts in that country. Nearly a million Jews owed their lives to Pius XII’s orders to hide them in the Vatican, convents, and monasteries, others were given false baptismal certificates showing they were Catholics, and other under the radar means. After the War the new Jewish nation publicly thanked Pius for all he had done and one of Rome’s Rabbis converted to Catholicism because of the Church’s actions.