Complex sentence: Following the Fourth Division Championship success in 1960--61, The Posh spent seven seasons in the 3rd Division before being relegated for financial irregularities in the summer of 1968.
Split into simpler sentences: Following the Fourth Division Championship success in 1960--61, The Posh spent seven seasons in the 3rd Division. They were relegated back to the 4th Division for financial irregularities in the summer of 1968.