After the 16th century the citadel was closely linked to the history of Kavala. The construction of the prison, the storage house for ammunitions and food that Evliya Çelebi found in the citadel in 1667, can be attributed to the construction activities that took place in the era of Suleiman the Magnificent who offered so much to the new city. As the storage house leans against the northern curtain (part of a wall amongst two ramparts) of the interior surrounding walls, it becomes obvious that it was built after the curtain. Its stonework, quite different to that of the rest of the citadel reinforced in the corners with stones that are more squared and without any bricks set in between, reminds us of the additions and repairs that Ottomans made in the second half of the 16th century in the castles of Morea (Methoni, New Navarino, the lower city of Monemvassia).
The increased defensive needs and primarily the alteration of the martial techniques applied, brought along certain changes in the citadel and particularly to the lower exterior surrounding walls: in its S.W. corner, the gate that connects the fortress directly to the centre of the new city is opened, while its SE corner is shaped into a rampart for the placement of artillery. The polygonal tower of its eastern curtain is filled up with earth. The light wooden flat roof of tower B of the NW corner is turned into a built chamber and the small ramp of the eastern curtain is manufactured in order to transport artillery to the top of the tower. At the same time, the bastions in the NW corner of the internal surrounding walls were turned into triangular and the polygonal rampant of the northern curtain received its current form.
Of course at times, several conversions took place, aiming at the placement of cannons and various repairs: one extensive alteration took place in 1656 and another one possibly after the destruction that the castle suffered from fire in 1684. Given the fact that after the first centuries, the danger of exterior attacks was almost non-existent, the citadel ceases to constitute a defensive centre of the region, as it initially was, and there are no longer reasons to keep preserving it systematically and guarding it with a large military force. From the mid 19th century the guard of the castle has been limited to 50 or 60 individuals, its cannons were obsolete, their maintenance was very bad and the practice of the guards was almost non-existent.
From the 17th century on, the castle also serves as a place of exile and imprisonment for the sultan’s subjects. In 1618 there were 100 prisoners here, Muslims as well as Christians, that were kept under wretched conditions, since the Ottoman authorities spent very little for them. In 1722 the governor of the fortress is ordered “to confine in the prison … until their chastisement” five bondsmen from Thessalonica, because they caused troubles during the collection of public revenues. In 1759 the deprived of his ranks pasha Ibrahim Kavagias is imprisoned here; in 1792 the small kotzabas (landowner) from Thassos Metaxas is imprisoned too, because he argued with the Voivod of Limnos. All these were jailed in the big dark dungeon that is known as a prison up to nowadays. In an “iliam” (judgement) of 1654 it is mentioned that a fire burnt a part of the castle’s wall. The skilled workmen Argyros and Vasilikos were immediately ordered to undertake the repairing. The expenses amounted to the sum of 80.000 akçe. According to the document in question, there were «dizdares» (inspectors of the walls) in the castle, Kethüda eri (the head of the guard of the High Gate), serdars (commanders in chief), mustafazes (governors of fortresses), azebans (sailors), janissaries etc. In a recording of 1618 it is stated that 100 people were imprisoned – Christians and Muslims – who received one akçe a day for food. With such a daily ration it is questionable if most of them survived at that time. From an order issued in 1715 we are informed that 4.019 cannons had been ordered for manufacture in the workshop of Praviste (Eleftheroupoli), destined to be sent to the castles of Kavala, Coroni (Corun), Methoni (Meton) and Navarino (Anavarin). What is interesting in this case, is the fact that the cannons were stored in the port of Kavala.
One reference to the fortress of Kavala, through the texts of various travellers that visited the city occasionally, is quite interesting. In the 1470’s, the city must not have been inhabited. “We passed from a mountain slope called Kavala. There is a narrow passage with two lovely castles one is on the mountain top and the other is near the sea – both of them are uninhabited” writes in his journal, the Venetian officer Angiollelo in the 1470’s. This is the oldest reference to the name “Kavala” as a place name (toponym). The uninhabited castles mentioned, are the castle of Christoupolis near the sea, which the Turks had built in 1425 and which they seem to have ceased to use in 1470, and the other, the “fortress near Christoupolis” on the mountain north of Christoupolis.
In 1667 Evliya Çelebi finds the fortress: “built on a high, smooth and black rock, on the edge of a narrow cape with two of its sides on the rock. It is highly solid and steep… It has the shape of an almond…” Its interior perimeter is 3.000 steps and its central gate is facing south. The citadel hosts the castellan (Disdar) and encloses within it ammunition (barut hanes) and food storage houses.
Robert de Dreux who passed by Kavala two years later (in 1669) describes the citadel as being separated into two wings with a large tower on top. The firing force of the citadel was not great – let’s keep in mind the fact that the city around its walls was also protected by the cannons of its walls overlooking the sea. At the time of Morosini’s attack against Kavala, 3 cannons are cited to be in the fortress. Later on, in 1786 Cousinery’s reports that there are 8 to 10 cannons in the citadel and this is where the castellan (disdar) along with a few men is hosted. In the 18th century, men of significance are imprisoned in the citadel (it is from this time on that the ammunitions and food storage house is renamed and called a prison). During this period or even a little bit later, as the very slipshod stonework proves, the little mosque was built above the reservoir.