Complex sentence: With such a manifesto, the number of Catholic representatives in the Prussian Diet rose considerably and in December 1870 they formed a new "Centre" faction, also called the "Constitution Party" to emphasize its adherence to constitutional liberties.
Split into simpler sentences: With such a manifesto, the number of Catholic representatives in the Prussian Diet rose considerably and in December 1870. They formed a new "Centre" faction, also called the "Constitution Party" to emphasize its adherence to constitutional liberties.