Byzanthamum is a city through door seventy-seven of the 100 Cupboards. It is filled with tall factories and bustling traffic. The city is controlled by the wizard Darius, though it once was under the oversight of Ron, who still lives there with his wife Nella. Henry York Maccabee and Richard both are taken to Byzanthamum by force. Byzanthamum is in a different world than Badon Hill and Hylfing.