[1] According to Damrong Rajanubhab, four kinds are distinguished in the Pāli Canon: "Relic [Dhatu], Memorial [Paribhoga], Teaching [Dhamma], and votive [Udesaka].
In pre-Buddhist India caitya was a term for a shrine or holy place in the landscape, generally outdoors, inhabited by, or sacred to, a particular deity.
In the Mahāyāna Mahāparinirvāṇa Sūtra, near the end of his life the Buddha remarks to Ananda how beautiful are the various caitya round Vaishali.
The final category, udesaka or uddesika cetiya, literally translates as "indicative reminders" or "votive objects", for example images of the Buddha.
Originally udesaka were secondary to paribhogaka and sārīraka, but with the influence of Greco-Buddhism, statues of the Buddha were produced in great numbers, followed later by paintings and other images.