Pope Benedict XVI made a heartfelt appeal for peace at an emotional memorial ceremony in Rome, March 27.

The Pope visited the site where 335 people, mostly Romans, were executed during World War II by the Nazi occupation forces.

The Pope and the chief rabbi of Rome, Riccardo di Segni, both prayed Psalms at what is now a mausoleum in the victims' memory.

Pope Benedict was joined by two cardinals as he entered the bunker-like monument and knelt before the rows of tombs to pray.

For one of them, Cardinal Andrea Cordero Lanza di Montezemolo, the act was deeply personal.

He was praying before the tomb of his father, Giuseppe, an Italian colonel among the murdered.

In a brief discourse that followed, Pope Benedict called the event of March 24, 1944 “a grave offense to God, because it was deliberate violence of man against man.

“It was the most deplorable effect of war, of any war; while God is life, peace and communion.”

Only the mercy of God can “fill the void, the abysses opened by men when, impelled by blind violence, they renounce their dignity as children of God and as brothers of one another,” he said.

Whoever and wherever he may be, man is the child of God and brother to rest of humanity, he added. Being “sons” and “brothers” is a status that must not be taken for granted but be sought, he said. “We must say yes to good and no to evil.”

The killings were carried out within an abandoned stone quarry near the Catacombs of St. Callistus known as the “Fosse Ardeatine.”

Under orders from Adolph Hitler, soldiers killed 10 prisoners and civilians for every Nazi life taken in a surprise attack that left 33 of their comrades dead.

In the rush to round up the victims before the 24-hour deadline imposed by the dictator, a total of 335 people were gathered up from local jails on March 24, 1944. They were serving time for all manner of real or fictitious crimes, for their opposition to the occupation or just for being Jews.

The Nazi soldiers detonated explosives to cover their tracks after they had committed the killings, drawing the attention of the Salesian fathers in charge of the nearby catacombs. They discovered the mass grave.

At the old quarry, the Pope said, the “painful memorial of the most horrendous evil, the real answer is to join hands as brothers, and say: 'Our Father, we believe in You, and with the strength of Your love we desire to walk together in Peace, in Rome, Italy, in Europe, throughout the world'.”

Cardinal Montezemolo told Vatican Radio on the anniversary that although the event has become “a page in history,” it cannot be forgotten.

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It “must continue to teach and remind on the one hand that there was a violent event, on the other hand that it represented a gathering of persons of different faiths who sacrificed their lives ... always with faith, with a strong faith. And this remains strong.

“These,” he said, “are the pages of history that give strength to the current and future generations.”