sentences:  Additional income, to the amount of 300,000 in the 18th/19th centuries, came from leasing a number of Aegean islands to tax farmers ().The heyday of the post was in the 16th century, when a succession of capable holders brought Ottoman naval power to its height, and for a time ensured its supremacy in the Mediterranean.Although in theory the post could only be filled by a serving admiral (), a chief of the Imperial Arsenal () or, at the very least, by the of Rhodes, from the turn of the 17th century the appointment of court favourites and/or persons lacking in military or naval experience marked the beginning of Ottoman naval decline.