As more details emerge about the watershed normalizing of diplomatic relations between the United States and Cuba, we're learning more about the instrumental role that Pope Francis played in helping to bring American and Cuban leaders together.

On Wednesday, a senior Obama administration officials spoke of an "extraordinary letter" written by the pope to President Obama and Cuban President Raúl Castro over the summer in which he urged the two men to mend the relationship between their countries.

As one official noted, the correspondence “gave us greater impetus and momentum for us to move forward.”

In a press conference on Wednesday, which also happens to be the pope's 78th birthday, President Obama credited Francis for his influential "personal plea" and thanked him for his "moral example."

In particular, I want to thank his Holiness Pope Francis, whose moral example shows us the importance of pursuing the world as it should be, rather than simply settling for the world as it is.

According to officials, Pope Francis brought up Cuba several times during his meeting with the president in March and, given Francis' significance as the first pope from Latin America, it's fair to assume that his clout likely helped bring Castro to the table as well.

Vatican officials were also said to have been present during the negotiations between the United States and Cuba, marking them the only other country to directly participate in the talks. While Canada reportedly hosted the majority of the secret meetings of the two sides, according to a Vatican statement, the pope also hosted Cuban and American representatives together earlier this year during the final deal was struck.

"The Holy See received Delegations of the two countries in the Vatican last October and provided its good offices to facilitate a constructive dialogue on delicate matters, resulting in solutions acceptable to both Parties."

On Wednesday, Cuban President Castro also thanked the pope in his address. "I want to thank the support of Pope Francis for the improvement of relations between Cuba and the U.S."