The hymns of the Rigveda are notably similar to the most archaic poems of the Iranian and Greek language families, the "Gathas" of old Avestan and "Iliad" of Homer. As the Rigveda was orally transmitted by methods of memorisation of exceptional complexity, rigour and fidelity, as a single text without variant readings, its preserved archaic syntax and morphology are of vital importance in the reconstruction of the common ancestor language Proto-Indo-European. Sanskrit does not have an attested native script: from around the turn of the 1st-millennium CE, it has been written in various Brahmic scripts, and in the modern era most commonly in Devanagari.