Degaldoruwa cave temple also known as Degaldoruwa raja maha viharaya was built by King Rajadi Rajasinha and his elder brother King Sri Rajasinha during the 18th Century (around 1771).
To give you a sense of time, this is around 5 years before the US Declaration of Independence. Comparatively, Ajanta caves in India date back at-least 1500+ years earlier.
It is interesting to note that the Rajasinha lineage is related to the Madurai Royal Family!
The temple is situated at, a village near Kandy Town. The temple had been built at a place where two rocks were touching each other from above and below. Pictures related to Buddhism are painted on the walls. The style of painting used is called as Kandyan era paintings. The paintings at the temple were the work of only four painters!!
The details of the constructions can be inferred from the copper plate grant which is called Degaldoruwa Thamba Sannasa.
Paintings on wall and the rock can be seen in the below picture. The green highlighted area is the one that appears on the stamp.