From the very beginning to the westernisation period, Ottoman rulers built their residence with a low-key and plain style only by considering their needs. The imperial buildings with classical architectural approach constructed regarding the requirements of the era are the structures surrounded with fortification walls, consisting of connected courtyards that were observed in previous Turkish States. There were gates, disconnecting courtyards, namely the entrance door (Bab-ı Sade), Imperial gate (Bab-ı Humayun) and the harem door in Manisa, Bursa, Edirne and Topkapı Palaces of Classical Period. These gates were used by the ruling class and named regarding the hierarchical structure of the management, and so the users used to be determined accordingly. Residents other than the administrators or those who came for various needs of the palace would use such doors as Bab-ı Selam (Gate of Salutation), Otluk and Koltuk. Everybody who came to the palace would enter the door determined according to their status. In addition, the palaces that had been constructed until the westernisation period expanded with some addings rather than just one construction. Ottoman Empire was having difficulties to keep up with the latest developments in Europe in the 17th century and first experienced stagnation and then regression periods. The management accepted this situation and tried to look for a way out. Therefore, some innovative movements were initiated. This period that started in the 17th century and lasted two hundred years is called "westernisation". In westernization period, the society confronted innovations in martial, political, cultural, artistic and social fields. During this process that also affected the architectural approach of the state, Western style started to influence architecture. Palaces (imperial buildings) have an important place among the most attractive and noticeable elements of Ottoman architecture. Considering that all the innovations were first adopted and applied by the management in that era, the imperial buildings of the era had become the primary architectural implementations. Western styles affected the architectural structure of palaces in westernisation period from a few aspects. First of all, palace buildings were constructed with only one construction together with its all parts. This situation indicates us the maturity level of Ottoman State governance and the management hierarchy. Then the courtyards disconnecting the units of palace disappeared and instead, landscaped gardens between these units were preferred. Another development is that palaces were built mainly by the sea; therefore, the construction of new gates that provided entrance from sea direction became a necessity. The transitions between the gardens disconnecting the units of palace were maintained through the gates as can be seen in Dolmabahçe, Çırağan, Beylerbeyi and Yıldız Palaces as the first examples. Each garden and gate was approached in a different style symbolising different units of the palace. Those doors built on the walls of palace or the fortification didn't lose their users and names despite the effect of westernisation. Even though they were in different places and configurations, they were able to protect their identities. Dolmabahçe palace, surviving until today, one of the four masonry palaces all located in Istanbul is the first and the greatest structures where the changes were felt. Two out of ten doors in Dolmabahçe palace namely "Gate of the Sultan (Saltanat Kapısı) and Gate of the Treasury (Hazine Kapı" are respectively bigger and more gorgeous. These gates also qualify as the signs showing the power of the rulers against Western countries and the public. In this sense, gates are of critical importance as they reflect the changing approach of Ottoman rulers who always preferred to live in a simple and plain way away from flashiness. When different implementations that do not exist in the other gates of Ottoman imperial structures during classical period are taken into consideration, there can be seen a differentiation in the Gates of Dolmabahçe palace. That's why; the identification of the origin of the architectural configuration of the building, its forms and decorations has become a necessity. The political, economical, cultural and artistic reasons leading to this new approach in the architecture of the Gates have been searched for. After some field studies and literature review over Dolmabahçe palace gates, they were compared with examples in Europe. In the imperial buildings of Europe in Baroque, Rococo and Neo-Classical periods, starting from renaissance period, it is observed that a change just as in Ottoman imperial architecture took place. The chateaus, residence of ruling class in Europe, were not on the high hills anymore but instead in central places near public. Also the approach of surrounding these residences of the ruling with thick walls was given up. Instead of thick walls, garden walls and gates were preferred. From this aspect, the change that Europe had gone through a few centuries ago is also observed in the palaces of Ottoman Empire in the westernisation period. Gate of the Treasury in Dolmabahçe palace is considered as a structure including all the mentioned changes. Gate of the Treasury in Dolmabahçe palace, one of the imperial architectural buildings of Ottoman Empire, maintains its importance both with its eclectical style reflecting the architectural approach of the era and its size and monumental structure as a symbol of power. [ABSTRACT FROM AUTHOR]