"The discourse on Warden Captain Mahmud, on [his] victories over the damned dwellers of Hell, the Maltese" is a rare specimen of Ottoman Tiefkultur novel of the late seventeenth century. Allegedly copied from a manumitted slave's letter to his former master, it describes the former's adventures when he set off from Alexandria to Istanbul. Written in a simple and lively language, this valuable text gives a great deal of information on intra-religious relationships in the Mediterranean, on the life of corsairs, but also on the ways Mediterranean seamen conceived the geography of the Sea; planned and understood their itineraries, viewed the various nations acting in the Levant, and so forth. After a study of the composition of the text and of its relations with similar texts in Ottoman literature, this paper tries to answer questions such as what type of 'cognitive/mental map' would Ottoman seamen have in mind in order to represent a known sea and its itineraries, what geographical markers did they use, how did they perceive a given sea. Analysis takes into account real maps, portolani and isolaria, as well as other similar sources.