The beatification of 233 martyrs -- the last step before possible sainthood, or canonization -- was the largest number ever in a single ceremony, reflecting the pontiff's determination to give his faithful many role models, including some from modern times.
The previous record was the 1877 beatification of 206 Japanese martyrs by Pius IX.
The pope declared the Spaniards, who died at the hands of leftists waging anti-clerical campaigns during last century's civil war, martyrs on Sunday.
Beatification usually requires the Vatican's certification of a miracle credited to the intercession of the person, but in the case of martyrdom, that requirement is waived.
Strong applause rang out when John Paul, reading his homily in Spanish, invoked the names of the newly beatified in a plea for an end to terrorism, blamed on Basque separatists, in Spain.
"Terrorism is born of hatred and, in turn, feeds it, it is radically unjust and increases the situations of injustice, gravely offends God and the dignity and rights of persons. With terror, man always comes out the loser," John Paul said, his voice sounding tired and at times quite hoarse during the two-hour ceremony.
"No motive, no cause or ideology can justify it," John Paul said. "Only peace can build peoples. Terror is the enemy of humanity."
A warm wind blew John Paul's hair during the ceremony on the steps of St. Peter's Basilica. About half the choirboys and many in the crowd of about 30,000 in St. Peter's Square wore sunglasses in the strong, late morning sun.
Almost all those beatified Sunday died in 1936 in the province of Valencia at the hands of leftist forces battling Gen. Francisco Franco. A few others were from Catalonia.
Civil war broke out when Franco led a revolt against Spain's leftist democratic government. Franco, generally regarded as a fascist, won the war, which claimed about 500,000 lives.
According to the Vatican, John Paul now has beatified 1,227 people in more than 100 ceremonies, and since becoming pope in 1978 has raised 477 candidates to sainthood.
In comparison, in the previous 400 or so years, a total of 1,310 candidates were beatified and 300 raised to sainthood.
John Paul called the latest group to be beatified a "model of coherence of life, constancy in faith and reconciliatory spirit."