Complex sentence: At around 1260, the Neuenburg-Strassberg noble family established the medieval town of Altreu, which was fortified with walls, trenches, and a castle; a wooden bridge over the Aare was also constructed at that time.
Split into simpler sentences: At around 1260, the Neuenburg-Strassberg noble family established the medieval town of Altreu, which was fortified with walls, trenches, and a castle. A wooden bridge over the Aare was also constructed at that time.