The Siege of Mechanicsburg was a battle that unfolded from Volume VII to Volume XIII of the Girl Genius story. It was a series of complicated engagements involving the Wulfenbach Empire, the Fifty Families, House Heterodyne, and a smorgasboard of lesser enemies and rebels. The siege ended inconclusively, with all main adversaries scoring significant successes that were rendered indecisive by critical setbacks, while most minor rivals were obliterated. The battle coincided with the successful claim of Agatha Heterodyne as the Heterodyne heir; it was suspended when Mechanicsburg was frozen in time, and precipitated the collapse of the Wulfenbach Empire.