ABSTRACT
Following the conquest of Rhodes in 1309/1310, Kos was the second most important territory held by the Hospitallers in their island empire (Figure 3.1). It was the seat of the Hospitaller governor of the islands of Leros, Kalymnos and Kos, 1 which were treated as an autonomous administrative unit. Bodrum, a Hospitaller castle on the Turkish mainland, faced Kos and formed one of the fixed points contributing to the defensive system as a whole. Several of the sites discussed below have never been described before, while possible solutions are offered to the mysteries of unidentified castles mentioned in the sources, and of one known castle whose name is unknown. Unlike the situation on Rhodes, 2 no overall plan survives to document how the islands were to be defended. However, enough evidence is available to suggest how the Hospitallers were able to hold on to their offshore islands until 1522. Map of Hospitaller islands of the Dodecanese https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315567495/4d07424a-b29d-4ed6-8ffd-a9693d7ef2d5/content/fig3_1_B.jpg" xmlns:xlink="https://www.w3.org/1999/xlink"/>
