After the death of Hermann von Mallinckrodt (1821–1874) in 1874, Windthorst became leader of the party and maintained that position until his death. It was chiefly owing to his skill and courage as a parliamentary debater and his tact as a leader, that the party held its own and constantly increased in numbers during the great struggle with the Prussian government. He was especially exposed to the attacks of Bismarck, who attempted, personally, to discredit him and to separate him from the rest of the party. And, he was by far the ablest and most dangerous critic of Bismarck's policy. The change of policy in 1879 led to a great alteration in his position: he was reconciled to Bismarck and even sometimes attended receptions at Bismarck's house. Never, however, was his position so difficult as during the negotiations which led to a repeal of the May laws.