Ellora is a basalt scarp cut with more than a hundred caves, Buddhist, Hindu and Jain, and the tidy story usually told about them has not survived scrutiny.
The conventional scheme
The standard account runs: Buddhist caves roughly 600-730, then Hindu 730-950, then Jain to about 1000. Three religions, in sequence, politely taking turns.
Why it is doubted
The styles overlap in ways the sequence does not explain, and dating rock-cut architecture is notoriously hard because there are no foundations, few inscriptions and no stratigraphy.
Some scholarship now argues that certain Hindu caves precede the Buddhist ones, which reverses the picture entirely. The chronology is genuinely unsettled, and the neat sequence should be treated as a convenience rather than a finding.
What is not in doubt is that the three traditions worked the same cliff over a span of centuries, in some periods concurrently. Whatever the relations between them were, they were not such as to prevent excavating monasteries within a few hundred metres of each other.
The Buddhist caves and Vajrayana
Caves one to twelve are Buddhist and span Mahayana into Vajrayana.
Caves eleven and twelve, Do Thal and Tin Thal, of three storeys each, carry tantric iconography including mandala arrangements and esoteric figures. This is among the better structural evidence that Vajrayana was institutionally established in South Asia by the eighth century, which matters because much of the textual evidence for early tantra is hard to date.
Kailasa
Cave sixteen is the extraordinary one, and it is not really a cave.
The Kailasa temple is a complete multi-storey Shaiva temple (gateway, courtyard, subsidiary shrines, elephants, free-standing columns, a two-storey main structure with a tower), carved downward out of the living rock as a single piece of stone.
The method inverts building. Masons began at the top of the hillside and cut down and inward, removing something like two hundred thousand tonnes of basalt, and everything that stands is what they chose to leave. There is no assembly, no joint, no possibility of correcting an error by replacing a block.
It is attributed to the Rashtrakuta king Krishna I in the eighth century and is thought to have taken on the order of two decades.
Still in use
Worship continues in places, notably at the Jain caves at the northern end, so Ellora is not purely a monument in the way Ajanta is.
UNESCO inscribed the site in 1983, the same year as Ajanta.