In the year 1334, the castle was completed and was at its largest. A few years later, the castle was damaged by the Basel earthquake on 18 October 1356, but it was soon restored to its original condition. At this time Konrad VIII (1324-1378), son of Hartmann I Münch von Münchenstein resided in Münchenstein castle. Konrad VIII (called "Hape") married Katharina, the hereditary daughter from Löwenburg, in 1340. Katharina Münch von Münchenstein-Löwenberg died in 1371 and Konrad VIII inherited governance of Muttenz and the three fortresses in the district Wartenburg.