Current quarters of the district are Cami-i Kebir, Kadı Mehmed Efendi, Sururi Mehmed Efendi, Yahya Kahya, Fetihtepe, Küçük Piyale, Piyale Paşa, Bedrettin, Çatma Mescit, Hacı Hüsrev, Kulaksız and Kaptan Paşa. According to the census in 1997, the total population of the “Kasımpaşa District” is about 100,000. 

Kasımpaşa and its vicinity were known as Pegai (sources) during the Byzantine period. It was known as Pegai Psihra Hidata (cold waters) in the later literature. As can be understood from such names, there are many waters, sources and creeks in the district. It is known that Basileos I had one summer palace and four chapels constructed in Pegai. It is reported in the literature that the palace survived until 921 and then it was ruined during the encompassment of Bulgaria when Byzantine armies were defeated and then repaired after some time. It is estimated that the palace was located on a high hill on the coast of Kasımpaşa. There was no settlement area in the district during the Byzantine period, but it was used as a recreation area. Upon the arrival of Muslims, Islam was widely embraced. 

Kasımpaşa was a monastery in old times and known as “ayalonka” by the non-Muslims according to the journals of Evliya Çelebi. After the Conquest of Istanbul, it was used as a Muslim Cemetery upon an imperial order. Also this area behind the shipyard in Kasımpaşa had been used as a cemetery as ordered by Mesleke and Eba Eyyub Ensari during the caliph Abdülmümin Melik’s period and then during the conquest of some part of Istanbul and a half of Galata by Harun Reşid and Yıldırım Bayezid. It is known that Sahabe-i Kiram and his esteemed sons were buried here. There are some signs written on Cufic stones in the cemeteries.

The Ottoman settlement in Kasımpaşa began with the conquest of Fatih. When the Turks arrived, this area was a vacant field outside the walls of Galata. Fatih The Conqueror had the first bridge constructed on the opposite shore of the Golden Horn after reaching the Golden Horn with his warships through Kasımpaşa (Kozluca) creek, which has now disappeared. In addition, according to Evliya Çelebi, “he had the cemeteries repaired, had a few small shipyards, Captain Pasha Ottoman’s house and one mosque constructed.” Istanbul shipyard, which would then be known as the Golden Horn shipyard, was constructed here and sailors from Lazistan and Karaman were brought in. According to Sadi Abaç, the original community living in Kasımpaşa are from İzmir and Gallipoli, although there were many sailors from Lazistan and Karaman. After the Conquest, the Golden Horn coast of Kasımpaşa had been a sailor’s settlement area as it is today. In 1516, the Gallipoli shipyard was also moved to Kasımpaşa. 

This area was first known as Kasımpaşa during the period of Suleyman The Magnificent. Evliya Çelebi, who was also born in Kasımpaşa, tells this story as follows: “During the period of Suleyman The Magnificent, when the population of Istanbul became very crowded, an imperial order was released to assign Vizier Kasım Pasha, the conqueror of Ayabolu, and Vizier Ayas Pasha, the conqueror of Alaüddevle as the officers responsible for the construction of the Kasımpaşa district. With the support of thousands of Ottoman notables, Kasımpaşa district was properly built up”. After such construction activities, the area took its name from Vizier Kasım Pasha, who constructed a Mosque and various buildings. 

Kasım Pasha was raised in the palace and was first assigned to a position outside the palace as the Stirrup Aga. Kasım Pasha, who had also twice worked as Governor of Egypt, was assigned to the construction of Kasımpaşa during the period of Suleyman The Magnificent. Kasım Pasha, who is supposed to be a Chief Admiral, could not be a Chief Admiral, even if he had been awarded with plumes. 

According to Schweigger, an itinerant, who visited Istanbul during the period of Suleyman The Magnificent, there were many slaves in Kasımpaşa and around the shipyard. According to this rumor, 12,000 slaves of Piyale Pasha were living in Kasımpaşa and most of them were employed in the shipyard. Schweigger reports that such slaves were living in comfort in this area, they were allowed to go to the public bath once a week and to worship in St. Pierre Fransisken Church in Galata on Sundays and they even had days off during holidays. But the protestant slaves were worshipping in the ships of the protestant states, since there was no protestant church in Istanbul. 

It is also written by Evliya Çelebi, the famous Ottoman itinerant, that the rulers of Kasımpaşa were the Galata Kadi according to Muslim canonical laws as well as Captain Pasha, the shipyard chamberlain and head officers according to state laws. Kasımpaşa had been the most prosperous and important districts of Istanbul in the 17thcentury. There are about ten thousand houses in Kasımpaşa according to the census in the period of Murat IV and the population was classified into three groups, i.e. as soldiers, tradesmen and merchants, and dervishes. Evliya Çelebi gives the distribution of craftsmen in the district as follows: He reports that calking masters and raft constructers from Benghazi and Egypt settled in Zindanarkası, forger Armenians in the Yeniçeşme Armenian Quarter, and iron forger and ring producer gypsies in Çürüklük and the upper areas. Robert Mantran also indicates that the most significant characters living in Kasımpaşa in that century were tradesmen and craftsmen. Such tradesmen and craftsmen were generally from tanner, gardener, carpenter and sailor communities. In addition to them, according to the itinerary, there were many brethren and dervishes in Kasımpaşa district. There were almost twenty dervish lodges in the district, including kadiri, rufai, halveti, celveti, uşşaki, and mevlevi lodges etc. 

Evliya, of course, did not forget the women of the district. He used the expressions of “very mannerly and chaste.” According to him; “There are many lovely ladies and gentlemen in Kasımpaşa,” because, the “weather of Kasımpaşa is very pleasant.” According to Mehmet Halil Bayrı, author of the book entitled Istanbul, the reason of Evliya’s praising the women of Kasımpaşa may be the fact that “he saw a gorgeous and eye-catching lady at every step.