Complex sentence: When the Council was dissolved, he was arrested, following Second Republic Government's instructions, in 19 August 1937, and he was kept in the San Miguel de los Reyes prison (near Valencia) for 38 days.
Split into simpler sentences: When the Council was dissolved, he was arrested by Spanish Republican Government's orders on 19 August 1937. He was kept in the San Miguel de los Reyes prison (near Valencia) for 38 days.