Complex sentence: The Speyer Cathedral is a very large and imposing basilica of red sandstone in Speyer, Germany Dedicated to Saint Mary and Saint Stephen, its official name is Mariendom but it is more often called Kaiserdom zu Speyer (Imperial Cathedral of Speyer).
Split into simpler sentences: The Speyer Cathedral is a very large and imposing basilica of red sandstone in Speyer, Germany. Its official name is Mariendom (Cathedral of St. Mary and St. Steven), but more often called Kaiserdom zu Speyer (Imperial Cathedral of Speyer).