It is located in the city center of Kayseri, next to the Grand Bazaar. Although it is known as the Great Mosque, it is also referred to as Cami-i Kebir or Sultan Mosque in different sources.

It was built by the Danishmend ruler Melik Mehmet Gazi in H.530/M.1135. The inion next to the door of the mosque opening to the north is a repair inion. Yağıbasanoğlu, one of the nephews of Melik Mehmet Gazi, was repaired by Muzaffereddin Mahmud in 1206. Atsuz Elti Hatun, the daughter of the same person, also repaired the Gülük Mosque in the same period. The repair inion, which is the only inion that the monument carries today, was placed on the outer face of the north wall, near the door. The repair inion includes the following statements: "This mosque was repaired by Yağıbasanoğlu, Muzaffereddin Mahmud, in H.602/M.1206, during the reign of Kılıçaslan's son, the great Sultan Keyhusrev - May Allah glorify his help."

The Great Mosque was damaged by the great earthquake that took place in 1716, and after being in a dilapidated state for 5-6 years, it was repaired in 1723 by the Matbah-ı Amire Emini (Palace kitchen manager) Hacı Halil Efendi from Kayseri. In this repair, the destroyed cone part of the minaret was also renewed, and the collapsed dome and minarets were also repaired.

The mosque, which sits on a floor of approximately 30m x 50m, is quite plain in appearance.

Although it is thought to have been converted from an old church or palace due to the columns belonging to Roman and Byzantine architecture used in it, it is a unique work of Islamic architecture with its architectural plan and pointed arch applications. The use of architectural elements such as columns used inside can also be seen in many mosques in our country.

The dimensions of the Great Mosque are 47.5 meters in length and 27 meters in width. The mosque has two domes. One was built in front of the mihrab and the other in the middle. It is thought that the mihrab dome, which has four rectangular windows, was built together with the mosque. However, the middle dome was probably added later.

It is thought that the Ulu Mosque was built according to the architectural plans in which the middle area seen in Seljuk mosques was left open and as a skylight, and it is understood that this opening was later covered with a dome. In this architectural plan, the mosques were built longitudinally and the middle part was left as an opening.

In the mosque, the feet and columns are connected to each other with arches. These arches are parallel to the short axis of the place of worship. The arches connecting the retaining points in the south are parallel to the long axis of the building. Its ceiling is 30 – 50 cm. It carries pine beams with diameters. A reed fence was placed on these beams. While this fence was covered with a thick earthen cover until recently, concrete has recently been laid. Since the ceiling is horizontal, the slope required for the rainwater to flow has been obtained by changing the thickness of the soil and now the concrete cover. The thickness is about one meter along the major axis. Stone gutter mouths are inserted into the outer walls.

The terrace is reached by an open linear staircase from inside the mosque. It is reached by a spiral staircase that reaches up to the balcony of the minaret. The differences between mosque architecture and minaret architecture show that the minaret was built later and it is understood that it was built later. However, there is no inion or record of when the minaret was built. However, this minaret is accepted as the oldest minaret of Kayseri. The minaret, which has a four-cornered pedestal made of stone, is completely bricked up to the balcony. Its height is 47 meters. Under the honour, there is a verse that has not been read yet, written in a beautiful Kufic on tiles.

There is a legend about the construction of the Great Mosque. According to this saying;

Melik Mehmet Gazi told his masters not to get help from anyone while building the mosque, and that the mosque would be for his own good.

An old woman who came to the construction of the mosque, stating that she is a widow, wants the 7 bricks she brought with her to be placed on the wall of the mosque for her own good. The foreman of the mosque does not accept this request of the old woman, reminding him that it is the order of Melik Mehmet Gazi. Melik Mehmet Gazi, who came to visit the mosque construction the next day, called the foreman and said that he could not sleep until the morning, saying, "They came into my dreams at night. They said that you upset an old woman and that if you don't use the bricks she brought, the life of the mosque will be as short-lived as the number of bricks." Upon the foreman telling the incident, Melik Mehmet Gazi orders the old woman to be found. The officials who dispersed to the city, after a long search, took the old woman who had 7 bricks in front of her house and brought them to the mosque construction. Kissing the old woman's hand, Melik Mehmet Gazi says, "Mother, our decision is not to upset you. We did not accept donations to prevent them from being in trouble because the people are poor. We will put the bricks you brought in the best part of the mosque," and the bricks are placed in a suitable place.

In the eastern part of the Ulu Mosque, there are still 7 bricks on the wall made with cut-off stones. And this was the source of the myth.