The walled grounds of Jerez can still be followed easily. This Almohad work from the twelfth century is supported on an irregular quadrilateral with a gate at every side. The Fortress stands on one of the angles. The relevance of this walled monument was due to the fact that Jerez was a bordering city and a basic strategic link. The perimeter of the walls was about 2,50 miles and the surface area covered about 16.60 square miles.
The Fortress is at the south-east angle of the wall, at the entrance to Jerez from El Puerto de Santa Maria. The position of the building is fixed by the following towers:
- The Octagonal Tower
- The Albarrana Tower in which you can see the characteristic double construction materials with stones and bricks. Almohad buildings usually contain these two elements.
- The Tribute Tower in which Alcaide Garci Gomez Carrillo became specially brave as it was recorded on the stone plaque laid on one of the fronts.

- Finally, the Ponce de Leon Tower which is next to the Tribute Tower. They both form a group whereas Ponce de Leon Tower was built in the fifteenth century.

The Baths and the Mosque are within the Fortress. The entrance to the Mosque is located at the rear side of the Cathedral so that you can see that large temple from the Muslim monument. The Mosque has a considerable history as it was built eighth centuries ago.

A Courtyard at the entrance, a tower or Minaret from which faithful Muslims were encouraged to pray, a little Courtyard for ritual ablutions and the Prayer Room with a niche or Mihrab facing Mecca were characteristic elements of an oratory. All this was transformed into Saint Mary´s Chapel as Christian troops occupied Jerez in 1.255. No alteration was caused and it became the eldest Marian worship chapel in the province.

Due to the Mudejar uprising and the Castilian garrison extermination, the chapel was burned as the very king Alphonso´X the Wise tells us in one of the Cantigas dedicated to that oratory: «et foron nola quemaren/mais sol nunca pod'arder». The content of the texts are so emotive and poetic that they give us the key of the events which took place there. After the definitive conquest of the city in 1.264, the chapel was restored and the plain wooden cover was replaced by the current pointed dome. Besides, the image of Saint Mary was put in the Chapel after a solemn procession with the king, the queen and the infants.

From then on, it became a local worship centre and was favoured with different privileges up to the sixteenth century. At that moment, The rundown condition of the historic chapel made it be moved. So, the former Muslim Baths in the very Fortress were fitted out for it. King Alphonso´X the wise dedicated some Cantigas whose resumed texts are currently engraved on two stone plaques laid at both sides of the altar.