It maintained close ties with European civilisations including the Roman Empire.For example, Bhatikabhaya (22 BC – AD 7) sent an envoy to Rome who brought back red coral, which was used to make an elaborate netlike adornment for the Ruwanwelisaya.Sri Lankan Bhikkhus studied in India's famous ancient Buddhist University of Nalanda, which was destroyed by Bakhtiyar Khilji.
Inside this protective enclosure were gardens, ponds, pavilions, palaces and other structures.
Among other structures, large reservoirs, important for conserving water in a climate with rainy and dry seasons, and elaborate aqueducts, some with a slope as finely calibrated as one inch to the mile, are most notable.
Sri Lankan monarchs undertook some remarkable construction projects such as Sigiriya, the so-called "Fortress in the Sky", built during the reign of Kashyapa I of Anuradhapura, who ruled between 477 and 495.
The Sigiriya rock fortress is surrounded by an extensive network of ramparts and moats.
He established the Kingdom of Tambapanni, near modern-day Mannar.
Vijaya (Singha) is the first of the approximately 189 native monarchs of Sri Lanka described in chronicles such as the Dipavamsa, Mahāvaṃsa, Cūḷavaṃsa, and Rājāvaliya (see list of Sinhalese monarchs).
The current constitution stipulates the political system as a republic and a unitary state governed by a semi-presidential system.
It has had a long history of international engagement, as a founding member of the South Asian Association for Regional Cooperation (SAARC), and a member of the United Nations, the Commonwealth of Nations, the G77, and the Non-Aligned Movement.
He built Ruwanwelisaya, the second stupa in ancient Sri Lanka, and the Lovamahapaya.
During its two and a half millennia of existence, the Kingdom of Sri Lanka was invaded at least eight times by neighbouring South Asian dynasties such as the Chola, Pandya, Chera, and Pallava. The Fourth Buddhist council of Theravada Buddhism was held at the Anuradhapura Maha Viharaya in Sri Lanka under the patronage of Valagamba of Anuradhapura in 25 BC.
Biso Kotuwa, a peculiar construction inside a dam, is a technological marvel based on precise mathematics that allows water to flow outside the dam, keeping pressure on the dam to a minimum.