- Indo-Aryans initially resided in the area around/ beyond the Black Sea, and were familiar with cold and long dawns (as evidenced by some parts of the Vedic texts - long ashvina-shastra to be recited at dawn).
- They radiated out widely, merged with and dominated prior occupants in vast tracts of Eurasia (just as they did in India, Iran etc..). Half of Western European men descended from one Bronze Age ‘king’.
- The IA invaders had “dharma” and a highly effective conservative core, which gave them the edge. (It is not some teme like chariots or gene like lactose tolerance which can explain the massive invasion from the Ural area into Europe and Asia.) This effective structure transferred over quite easily to each land they spread to, leading to secondary expansions such as that of the Dravidians into South India, NE India, SE Asia.
- In India, they similarly merged with a faction of IVC people. Steppe ancestry seen in BMAC first ~2100 BCE.
- Early Arya society consisted of common people (the vish), kShatriya-s and brAhmaNa-s - the lattter formed the elite, and were relatively fluid in early times. The vish might have traded with core IVC people long before the invasions.
- The core portions of RV or even YV far predate their invasion of India. Just equinoctial position indicated by the naxatra-sUkta puts it at around 2200BC, not to mention Thuban, other relatively oblique astronomical references.
- They came in multiple waves. The late RV sarayu and gomati were to the west. They were later moved east perhaps indeed with the movement of ikShavAkus.
- Along with that came great tumult and civil war (eg: mahAbhArata). In the end, kuru-pAnchAla realm was where major brAhmaNa vedic consolidation happened. Gradually, this culture and its carriers (mainly in the form of brAhmaNa-s) spread elsewhere in India and beyond. The hymns were recast, reorganized and their preservation was there shored up.