The archaeological heritage of Sri Lanka is divided in to three ages as Prehistoric, Protohistoric and historical periods. The presence of man activities in Sri Lanka probably dates from 75,000 years ago. Prehistoric sites which are presently identified in the country are distributed from the maritime belt and the lowland plains of the wet and dry zones to the high plateaus and rain forest in the central and south western mountain region of the island. The protohistoric period expands from about 1000 BC to the historical period at about 500 BC. The main indicators of the distribution of protohistoric and early settlements in the island are the megalithic burials and pottery sites. The beginning of the historical period of Sri Lanka is traditionally assigned to the reign of king Devanampiya Tissa when the Buddhism was introduced to Sri Lanka by the missionaries sent by the Indian emperor Ashoka. However the first clear information about the establishment of building and structures are dated back to the time of king Pandukabhaya. Sri Lanka's political and religious history is mainly set out by the ancient chronicles as well as over 4,000 stone inscriptions from 3rd century BC onward. Which give the history in considerable detail from the 3rd century and less reliably back to the 6th century BC. Sri Lanka has more than 250,000 identified archaeological sites throughout the country and some of them have been declared as archaeological reserves and protected monuments by the Sri Lanka archaeological department. Archaeological reserves are the sites consist of archaeological remains which are under the direct control of the archaeological department. Protected monuments are privately owned but scheduled under section 18 of the Antiquities Ordinance No.09 of 1940.
Declaration of monuments
According to the sections 16, 17, 18 and 19 of the Antiquities Ordinance No.09 of 1940, the minister who is the in charge of the subject may declare the ancient monuments by notification published in the governmentGazette. Also under sections 16, 17 and 19, ancient buildings and trees on state or private lands, may be declared as ancient monuments to provide safety and protection for them. Ancient construction with historical and archaeological value which are over 100 years of age can also be declared as ancient monuments in terms of the provisions of the Antiquities Act No. 24 of 1988.