Complex sentence: But, contrary to his hopes, a majority of the monarchists did not follow his pleas for cooperation, many of whom backed the aspirations of Germany, and who had hoped to see the victory of the Kaiser, as another channel to restore the monarchy.
Split into simpler sentences: But, contrary to his hopes, a majority of the monarchists did not follow his pleas for cooperation. Many of them backed the aspirations of Germany, and had hoped to see the victory of the Kaiser as another channel to restore the monarchy.