Complex sentence: Manuel Ramírez Escudero was one of the main promoters of the museum and since 1928 chaired the Board of Trustees of the same, a position that he held until 1967.
Split into simpler sentences: Manuel Ramírez Escudero was one of the main promoters of the museum. Since 1928, he has chaired the Board of Trustees of the same, a position that he held until 1967.