Complex sentence: The fortification had been originally constructed in the medieval style and, in the reign of Siegfried II of Westerburg (1275--1295), it successfully resisted a five-week siege by the Count of Cleves.
Split into simpler sentences: The fortification had been originally constructed in the medieval style. In the reign of Siegfried II of Westerburg (1275--1295), it successfully resisted a five-week siege by the Count of Cleves.