Exultavit cor nostrum is a letter, also known as a Papal bull

Papal bull

A Papal bull is a particular type of letters patent or charter issued by a Pope of the Catholic Church. It is named after the bulla that was appended to the end in order to authenticate it....

, from Pope Urban IV

Pope Urban IV

Pope Urban IV , born Jacques Pantaléon, was Pope, from 1261 to 1264. He was not a cardinal, and there have been several Popes since him who have not been Cardinals, including Urban V and Urban VI.-Biography:...

 to the Mongol Ilkhanate

Ilkhanate

The Ilkhanate, also spelled Il-khanate , was a Mongol khanate established in Azerbaijan and Persia in the 13th century, considered a part of the Mongol Empire...

 leader Hulagu

Hulagu Khan

Hulagu Khan, also known as Hülegü, Hulegu , was a Mongol ruler who conquered much of Southwest Asia...

 in 1263/1264.

The letter was evidently in response to a message brought to Urban by John the Hungarian, who claimed to be the Mongol envoy (it was not uncommon for individuals to present themselves as envoys, even when they were not). According to John, Hulagu desired to become a Christian, and requested that Urban send a representative who would help to baptise him.

Pope Urban responded with the Exultavit, which indicated that Urban had heard of Hulagu's sympathies towards Christianity through other sources. Urban cautiously welcomed Hulagu's envoy, and announced that William II of Agen

William II of Agen

William II of Agen was the Latin Patriarch of Jerusalem from 1261-1270. Among other things, he was tasked by Pope Urban IV in 1263 by the papal bull Exultavit cor nostrum to investigate the legitimacy of an alleged ambassador with the Mongol Empire, John the Hungarian.-References:* Peter Jackson,...

, Latin Patriarch of Jerusalem

Latin Patriarch of Jerusalem

The Latin Patriarch of Jerusalem is the title possessed by the Latin Rite Catholic Archbishop of Jerusalem. The Archdiocese of Jerusalem has jurisdiction for all Latin Rite Catholics in Israel, the Palestinian Territories, Jordan and Cyprus...

, would be investigating further.

John the Hungarian

Little is known of John the Hungarian, except that he had some standing in Hulagu's court, was referred to in the Exultavit, and was possibly the intermediary between Hulagu and the Christians. However, when he arrived to Pope Urban, though John claimed to be Hulagu's envoy, he had no letters of credentials. He reportedly brought a letter written by Hulagu in Maragha on April 10, 1262, dated the Year of the Dog

Year of the dog

Year of the dog may refer to:* Dog , an animal in Chinese astrology.* Year of the Dog , a film written and directed by Mike White.* Year of the Dog...Again, a music album by rapper DMX.* The Year of the Dog , a 1994 Russian film...

, and John's purpose was to transport the letter to King Louis IX of France

Louis IX of France

Louis IX , commonly Saint Louis, was King of France from 1226 until his death. He was also styled Louis II, Count of Artois from 1226 to 1237. Born at Poissy, near Paris, he was an eighth-generation descendant of Hugh Capet, and thus a member of the House of Capet, and the son of Louis VIII and...

. According to the historian Jean Richard

Jean Richard (historian)

Jean Richard is a leading French historian, who specializes in medieval history. He is an authority on the Crusades, and his work on the Latin missions in Asia has been qualified as "unsurpassed". Richard is a member of the Institut de France...

, its wording "bore signs of the intermediary of a western scribe, probably the Ilkhan's Latin notary, Rychaldus

Rychaldus

Rychaldus, Richaldus or Richardus was a clerk and translator for the Mongol Ilkhanate rulers Hulagu Khan, and then Hulagu's son Abaqa Khan...

." The letter followed the usual form of Mongol communications, expecting submission. It also referred to a gift received by the previous envoy Andrew of Longjumeau, and explained that the Mongols had previously thought that the Pope was the leader of the Christian people, until "it had been realized where true power lay among the French." The letter went on to describe previous Mongol campaigns such as against the Assassins, and suggested joint efforts between the Mongols and the Christians against their common enemy, the Egyptian Mamluk

Mamluk

A Mamluk was a soldier of slave origin, who were predominantly Cumans/Kipchaks The "mamluk phenomenon", as David Ayalon dubbed the creation of the specific warrior...

s. The letter also expressed Hulagu's desire to return Jerusalem to the Christians. King Louis sent John and the letter along to Pope Urban, and John probably returned to Maragha in late 1262.