The Turkish rulers utilized the services of the local designers and craftsmen who were among the most skilful in the world. The new fusion that started to take place avoided the extreme simplicity of the Islamic architecture and the lavish decoration of the earlier Indian architecture. Among the first buildings to be erected were the mosques at Delhi and Ajmer by Qutbddin Aibak. The mosque built in Delhi was called the Quwwatul Islam mosque. It measured about 70x30 meters. The central arch of this mosque which is decorated with beautiful sculptured calligraphy still stands and is about 17 meters high and about 7 metres wide. The successor of Qutbuddin Iltutmish was a great builder. He further extended the mosque. He also completed the building of the Qutb Minar which had been started by Qutbuddin and now stood in the extended courtyard of the mosque.
This is a tower rising to a height of about 70 meters and is one of the most renowned monuments of India. The next important buildings belong to the reign of Alauddin Khalji. He enlarged the Quwwatul Islam mosque still further and built a gateway to the enclosure of the mosque, the Alai Darwaza. Decorative element was introduced to beautify the building. He also started building a minar which was designed to be double the height of Qutb Minar but the project remained unfulfilled. The Tughlaqs concentrated on the building of new cities in Delhi like Tughlaqabad, Jahanpanah and Ferozabad. A number of buildings was erected which differed in their style from the earlier buildings. Massive and strong structures like the tomb of Ghiyasuddin Tughlaq and the walls of Tughlaqabad were built. The buildings of the Tughlaq period were significant from the point of view of the development of architecture. They were not beautiful but massive and very impressive.