 In 1684, Malebranche also responded to Arnauld’s Idées, and after a further exchange on the topic of the nature of ideas the debate turned to the theological issues concerning divine providence, grace and miracles. The battle became increasingly bitter, and as a result of a campaign on the part of Arnauld and his supporters, Malebranche’s Nature et grâce was put on the Catholic Index librorum prohibitorum (Index of Prohibited Books) in 1690 (the Recherche was added in 1709). The Malebranche-Arnauld polemic continued even after Arnauld’s death in 1694, with the publication in 1704 of Malebranche’s responses to earlier letters from Arnauld.