Ancient Buddhist monastic architecture constitutes a great part of the Archaeological Heritage of Sri Lanka. The origin of some of the monasteries dates back to the 3rd Century BC. The development of Sri Lankan Buddhist monastic settlements has taken two distinctive directions.   The first development which could be designated as ‘closed’ type commenced with the conversion of natural caves located in the forest into settlement of monks which dates back to the 3rd century BC which could be named as Forest Monasteries. Besides the caves which are used as residences of monks, there are references to other buildings which were used for common purposes. The distinctive feature of this type is the absence of ritual buildings such as Stupa, Image House, Asanaghara, etc.

The second monastic development could be designated as ‘open’ type first seen primarily concentrated in the vicinity of the capital city of Anuradhapura and later spread all over the country. Which in the confines of these monasteries were constructed all the buildings required for monastic purposes. These monasteries have major ritual buildings either as a large Stupa as a focal point of a sacred edifice as the focal point.

The main feature of the Rajagala Monastic complex is the construction of the monastic complex with the mixture of both ‘closed ‘and ‘open’ type which could be identified as a meditation monastery. It has its own Buddhist architectural character showing part of the monastic residential buildings are created by converting natural rock out crops converted to residential buildings of the monks while some of the residential buildings are built in different natural locations within the site. It is remarkable the layout of the buildings within the natural forest blending to the environment connected with manmade paths which are constructed to blend with the natural environment.

The buildings such as meditation walks, toilets are also built together with the private cave or constructed buildings which are not accessible to the general public. There are several manmade small and large ponds in the natural setting which has been created to obtain the water requirements of the monks. The common buildings in this monastery, such as Stupa, Asanaghara, Danasalawa, Janthadhara, Assembly Hall, Small Tank, etc., which could be accessed to the general public, are located in a central location easily accessed by the village settlement as well as the monks residing either in cave or constructed dwellings.  The special feature of this monastery is the construction of all buildings which are interconnected with paths and accessible stone stairways blending to the natural forest which created a distinctive combination of cultural and natural environment.

The work of Rajagala Archaeological Reserve was commenced in 2012 by the Department of Archaeology with the commencement of an exploration mission. After completing part of the exploration programme a research excavation camp was commenced in June 2012. The unidentified building near the two stupas was to be investigated during this camp. In July 2012 the Department of History and Archaeology of the University of Sri Jayewardenepura was invited to take over the site as the Department of Archaeology could not continue the archaeological work due to lack of manpower. An agreement was signed between the Director General of Archaeology and the Vice Chancellor of the University on the 22ndAugust 2012 and the site was handed over to the University on the 01st September 2012.The initial cost of the project was Rs. 89,082,512.37. According to the proposal submitted to the 2013 AFCP Large Grant programme a sum of US $ 100,000.00 which is equivalent to Rs. 12,738,000.00 has been donated in conserving the build cultural edifices in the common area only which was accessible to the general public during the operation of the meditation monastery. The agreement between the Department of Archaeology and the University of Sri Jayewardenepura was extended till March 2020 by a Memorandum of Understanding signed on the 17th June 2015; the total project cost is Rs. 323,897,373.14.In August 2015 a Cabinet Memorandum was submitted requesting the continuation of funds for the completion of the project by 2020. Cabinet of Ministers has approved the provision of Rs. 214.654 million from the Government Consolidated Fund in 5 years commencing from the year 2016 was approved by the Cabinet Decision on the 06th August 2015.According to the proposal submitted to the 2015 AFCP Large Grant programme a sum of US $ 150,000.00 which is equivalent to Rs. 19,500,000.00 has been donated for the preparation of a detailed survey plan and in conserving the some of the build cultural edifices. A total of Rs. 88,495,315.96 has been spent up to the end of December 2015.