On November 10, 1961, she received a Doctor Honoris Causa in Historical Sciences by Moscow State University for her contributions to the development of Marxist theory. In her acceptance speech she asserted that class struggle is the motor of history. In 1962 she attended the 10th Congress of the Italian Communist Party held December 2–8 in Rome where she met Socialists, Christian-Democrats and some church representatives. To the clerics she remarked, "We are not as wicked as you think, and we are not as good as we probably think we are." During the first few months of 1963 Ibárruri unsuccessfully appealed for the Spanish government to spare the life of executive committee member Julián Grimau. Before his execution Grimau wrote to Ibárruri saying, "My execution will be the last one." On the week of May 13 Ibárruri unveiled a plaque in his honour on Building 11, Block 1, of newly renamed Grimau Street in Moscow. On December 5 she arrived in Havana to commemorate the 5th anniversary of the Cuban Revolution. Cuban leader Fidel Castro invited Ibárruri to move permanently to the island, but she declined.