Complex sentence: For those who could not leave their homes, he later formed the Third Order of Brothers and Sisters of Penance, a fraternity composed of either laity or clergy whose members neither withdrew from the world nor took religious vows.
Split into simpler sentences: For those who could not leave their homes, he later formed the Third Order of Brothers and Sisters of Penance. This was a fraternity composed of either laity or clergy whose members neither withdrew from the world nor took religious vows.