Cohen said wartime Pope Pius XII should have done more to help Jews
A Jewish cleric has addressed a worldwide gathering of Roman Catholic Bishops for the first time.
Shear-Yashuv Cohen, chief rabbi of the Israeli city of Haifa, explained to the Pope and his bishops the importance of the Bible to Jewish believers.
He also used the occasion to denounce the Iranian president for his comments about Israel at the UN last month.
The first day of the Vatican Synod saw some strong opinions expressed, the BBC's David Willey in Rome says.
Not only did the bishops cover the role of the Bible in the modern world - the official theme of the discussions - but also international politics and the world financial crisis.
Pope Benedict XVI described the current financial crisis as proof that the pursuit of money and success is pointless. "Only the word of God endures," he told the synod.
Before the gathering of 253 bishops, Rabbi Cohen spoke of the "long, hard and painful history" of relations between Catholics and Jews, describing it as "a history of blood and tears".
He said his presence at the synod sent a signal of "hope and a message of love, co-existence and peace for our generation, and for generations to come".
And he appealed for all religious leaders to defend and protect Israel from outside threats.
President Mahmoud Ahmadinejad told the UN in New York last month that Israel "is on a definite slope to collapse and there is no way for it to get out of the cesspool created by itself and its supporters".
Without mentioning the Iranian president by name, Rabbi Cohen said Israelis felt "deep shock at the terrible and vicious words" he had uttered against their nation.
Canadian Cardinal Marc Ouellet, chief rapporteur of the synod, stressed the importance of dialogue with both Jews and Muslims.
"Bearing in mind the tragic history of the relations between Israel and the Church, we are invited... to repair any injustice committed against the Jews," he said.
The history of Christian persecution of Jews includes genocide, exile, pogroms, crusades and anti-Semitism going back several centuries.
Cardinal Oullet described Muslims as "allies in the defence of human life and in the assertion of the social importance of religion".
The Vatican will be hosting a major meeting with Muslim clerics and scholars in November as part of the Pope's plan to improve relations with the Islamic world, says our Rome correspondent.
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