Complex sentence: He moved that the title of pater patriae "should be bestowed upon Augustus and yet resigned the appointment of Prefect of the city after six days" tenure of office in 25 BC, because it was opposed to his ideas of constitutionalism.
Split into simpler sentences: He moved that the title of "pater patriae" should be bestowed upon Augustus. Yet he also resigned from the post of Prefect of the city in 25 BC after six days of holding this office because it conflicted with his ideas of constitutionalism.