Catholic officials in Cuba have expressed gratitude and even surprise at the communist government’s response to the death of Pope John Paul II, included three days of national mourning, according to the Associated Press.

The Cuban flag was to fly at half-staff on public buildings and military installations for three days, and several events, including anniversary celebrations for communist organizations and baseball games, were suspended, the AP said.

Cuban president Fidel Castro, along with other high-ranking communist officials attended Mass at the Cathedral of Havana. It was the first time the president has assisted the cathedral since his sister’s wedding in 1959 and the third mass he has participated in since the revolution, according to the British Broadcasting Corportation.

“Rest in peace, tireless fighter for friendship among peoples, enemy of war and friend of the poor,” wrote Castro in a condolences book at the Papal Nunciature, the Vatican’s mission in Havana, said the Associated Press.

Castro was also thankful to the Pope for speaking out against the U.S. trade embargo in a January 1998 visit.

“This earned you the gratitude and affection of all Cubans forever,” Castro wrote.

The Cuban government had announced it would send a high-level delegation to the Pope’s funeral on Friday in Rome.

Cuba had been an officially atheist country since 1959, the time when Castro came into power. In 1991, the government removed references to atheism in the constitution and allowed religious believers to join the Communist Party, according to AP.