In his later years his health steadily declined. He then developed a urinary tract infection that lead to septic shock. He died of heart failure from profound hypotension and complete circulatory collapse from the septic shock.
In 1913 Pius X suffered a heart attack, and subsequently lived in the shadow of poor health. In 1914, the Pope fell ill on the 15 August, an illness from which he would not recover. His condition declined and he died on 20 August 1914.
Pope Leo X survived an attempt by the cardinals to poison him in May 1517 and died on 21st December 1521, possibly by poisoning or as a result of chronic ill-health. He left the Vatican's treasury completely empty and various banks and lenders with enormous unpaid debts.
Pope Pius XII has not been canonized ( made a saint) yet; the last Pope that was canonized was Pope St. Pius X. Since I don't know which one you are asking about, I will give the answer for them both.
Pope St. Pius X ( Giuseppe Sarto) was Pope from 5 August 1903 to 20 August 1914. He was born 2 June 1835 in Riese. When he died on 20 August 1914 he was in the Papal Apartment of the Apostolic Palace in Vatican City.
Pope Pius XII (Eugenio Pacelli) was Pope from 2 March 1939 to 9 October 1958. He was born 2 March 1876 in Rome. He died at Castel Gandolfo ( the Papal summer residence) on 9 October 1958, which is about 14 miles from Vatican City. There are four steps in the process of being made a saint, and Papa Pacelli is on the 2nd (Venerable). I will be very happy when he is made a saint. I think he is one of the holiest and most Christ-like people to ever live, and he is an inspiration to me every day!
Summer
From Wikipedia:
Pius XII died on 9 October 1958 of acute heart failure brought on by a sudden myocardial infarction in Castel Gandolfo, the Papal summer residence. His doctor Gaspanini said afterwards: "The Holy Father did not die because of any specific illness. He was completely exhausted. He was overworked beyond limit. His heart was healthy, his lungs were good. He could have lived another 20 years, had he spared himself."
Pope Pius had already been ill for some time when, on 25 November 1938, he suffered two heart attack within several hours. He had serious breathing problems and had to stay in his apartment
He died in the Apostolic Palace in the Vatican on August 20, 1914.
Benedict XV fell ill with pneumonia in early January of 1922 and succumbed to that illness on January 22, 1922.
Benedict XV died on January 22, 1922, in the Apostolic Palace of the Vatican.
St. Benedict and Pope Benedict XV.
Pope Benedict XV was born on November 21, 1854.
Pope Benedict XV was born on November 21, 1854.
Benedict XV served as pope for 7 years and 141 days.
Pope Benedict XV died on January 22, 1922 at the age of 67.
Pope Benedict XV was the pope in 1920.
Giacomo Paolo Giovanni Battista della Chiesa was the birth name of Pope Benedict XV.
Pope Benedict XV's statute stands in the courtyard of St Esprit Cathedral, Instanbul Turkey.
The statue of Pope Benedict XV stands in the square in front of the Cathedral of the Holy Spirit, in Istanbul, Turkey, a Moslem country.
Benedict XV is buried in a tomb in the crypt under St. Peter's Basilica in the Vatican.
He chose the name Benedict to honor two individuals he greatly admired - Saint Benedict of Nursia and Pope Benedict XV.