Complex sentence: After the departure of Amadeus, Ruiz Zorrilla advocated the establishment of a republic, but he was not called upon either by the Federal Republicans to help them during 1873 or by Marshal Serrano in 1874 to join Martos and Sagasta in his cabinet.
Split into simpler sentences: After the departure of Amadeus, Ruiz Zorrilla advocated the establishment of a republic. Notwithstanding this, he was not called upon either by the Federal Republicans to help them during 1873, or by Marshal Serrano in 1874 to join Martos and Sagasta in his cabinet.