Complex sentence: Rib vaults were added in the nave and choir and in the windows the Romanesque rounded arches were replaced with Gothic pointed arches while the steeple roof was made octagonal, a common feature in many Danish Gothic buildings.
Split into simpler sentences: Rib vaults were added in the nave and choir and in the windows the Romanesque rounded arches were replaced with Gothic pointed arches. The steeple roof was also made octagonal which is a common feature in many Danish Gothic buildings.