In an unusual letter to the world’s Catholic bishops, Pope Benedict has acknowledged Vatican mistakes in the case of Holocaust denier Richard Williamson.

Benedict said the controversy resulted from an “unforeseen mishap” that made his efforts of “mercy” toward the excommunicated bishops seem like a repudiation of reconciliation between Christians and Jews.

“That this overlapping of two opposing processes took place and momentarily upset peace between Christians and Jews, as well as peace within the church, is something which I can only deeply deplore,” he wrote.

Benedict wrote that he was saddened that even who should know better “thought they had to attack me with open hostility.”

Here’s the full text of the Pope’s letter…