The chronology of "Brihadaranyaka Upanishad", like other Upanishads, is uncertain and contested. The chronology is difficult to resolve because all opinions rest on scanty evidence, an analysis of archaism, style and repetitions across texts, driven by assumptions about likely evolution of ideas, and on presumptions about which philosophy might have influenced which other Indian philosophies. Patrick Olivelle states, "in spite of claims made by some, in reality, any dating of these documents (early Upanishads) that attempts a precision closer than a few centuries is as stable as a house of cards".