The Sultanate period brought to India new styles of art and architecture which were soon absorbed into the existing set up. A number of factors were responsible for events to move in such a direction. The existing Indian styles and the new ideas had many common features, which allowed them to adapt to one another. For instance both the temple and mosque had large open courtyards. Also many temples were converted in mosques by the foreign invaders, and this created a blend of Indian as well as foreign styles.
The Sultanate introduced two new architectural ideas, the dome and the pointed arch. The dome was an important decorative structure in Islamic buildings, and soon was implemented in other structures as well. The pointed or true arch that was introduced during this period, was completely different from the type of arches that were being constructed within the country earlier. The earlier Indian style of creating arches was to first put up two pillars. The pillars would then be cut at intervals accommodate 'plug in' projections. There would be a sequence of squares that would gradually decrease in size creating an arch. The new artisans introduced the true arch. This was achieved by making the middle stone a key stone and to have the other stones distribute the load of on the two pillars.
The concept of the dome was also introduced. This was gradually perfected and one of the most stunning examples is the dome on top of the Taj Mahal. The dome initially started out as a conical dome as we see in the Mehrauli region in Delhi and eventually developed the ultimate bulbous onion shape on the Taj Mahal. The dome effect was achieved by an interesting method. A square base was first constructed and then at varying angles more of these squares were added to the base. This eventually create a rough dome effect. This was plastered to make it completely round and then the squares were removed. The use of concrete was also on the