Pope Francis warned ideological attempts to sow fear or division in society on Sunday as he paid tribute to Christians in Romania killed or persecuted under Communism.
His comments came on the final day of his visit too the majority-Orthodox country.
Francis travelled to the central city of Blaj to beatify seven bishops who died under the former Communist regime, either in prison or as a result of harsh treatment.
After the Second World War, Romanian authorities confiscated property from the Eastern Rite Catholic Church and forced its members to join the larger Orthodox Church, which was easier for party officials to control.
Looking tired from his schedule, the Pope beatified the bishops at an open-air mass, moving them one step closer to sainthood.
In his homily, Francis paid tribute to an estimated half-million Romanians jailed in the 1950s and early 60s, including politicians, priests and doctors. Around a fifth of them are said to have died in prisons and labour camps.
The Pope told the estimated crowd of 80,000 of the victims' courage.
“With great courage and interior fortitude, they accepted harsh imprisonment and every kind of mistreatment, in order not to deny their fidelity to their beloved church,” Francis said.
Many Catholic properties taken by the Communist dictatorship or given by the government to the Orthodox have yet to be returned 30 years after the fall of dictator Nicolae Ceausescu.
“(The bishops) endured suffering and gave their lives to oppose an illiberal ideological system that oppressed the fundamental rights of the human person,” Francis said.