Scholars approach the dating of the Rigveda by letting several streams of evidence converge, rather than relying on a single decisive proof. The most fundamental of these is linguistic analysis: the hymns are composed in a very archaic form of Vedic Sanskrit, older in grammar, sound patterns, and vocabulary than later Vedic texts and Classical Sanskrit. By comparing this language both with later Indian texts and with related Indo‑European languages such as Avestan and Old Persian, the Rigveda is placed early in the Indo‑Iranian linguistic continuum. Within the text itself, scholars also discern layers, with certain “family books” regarded as especially ancient, and this internal stratification helps to sketch a relative sequence of composition within the corpus.

Alongside language, the cultural and material world reflected in the hymns serves as another guide. The society described is that of semi‑nomadic or early agrarian clans, ruled by chieftains rather than by fully developed states, and the rigid caste system of later periods is not yet clearly visible in its classical form. The hymns speak of horse‑drawn chariots, cattle pastoralism, early agriculture, and a ritual life that is less systematized than in the Brāhmaṇas and Upaniṣads, while references to iron and large urban centers are absent. When this picture is set against archaeological horizons in northwestern South Asia—late Harappan and related cultures that show chariot use and pastoral, riverine life—it suggests a setting in the late Bronze Age or early Iron Age, after the decline of the mature Indus cities.

A further line of inquiry compares the Rigveda with the oldest Avestan texts of the Iranian tradition. Shared deities, ritual motifs, and a common stock of religious vocabulary indicate that both derive from an earlier Indo‑Iranian heritage. By bracketing the period in which this shared tradition must have begun to diverge, scholars gain an additional check on the relative age of the Vedic hymns. Internal references to social and religious developments, when aligned with this broader Indo‑Iranian background and with the later Vedic literature, reinforce the view that the bulk of the Rigveda predates the more elaborate ritualism and philosophical speculation of subsequent texts.

Astronomical and geographical hints are sometimes brought into the discussion, though with greater caution. The hymns contain evocative references to dawns, seasons, and celestial phenomena, and some have attempted to match these to specific astronomical configurations, but such efforts are widely recognized as uncertain because the verses are poetic and symbolic rather than technical. Descriptions of rivers, mountains, and tribal territories, especially in the northwest of the subcontinent, are therefore weighed more heavily than speculative star‑dating. When all these strands—linguistic, cultural, archaeological, comparative, and internal—are woven together, most scholars situate the composition of the oldest hymns roughly in the second half of the second millennium BCE, with the main body of the Rigveda completed before the first millennium BCE was well underway.