The collection has no single author, origin date or fixed original text. It grew across centuries by absorbing Persian (the Hezar Afsan), Indian, Arabic and Egyptian material, and some of its now most famous tales, including Aladdin and Ali Baba, are not found in the oldest surviving Arabic manuscripts at all. Those two tales entered the collection's Western reputation only through Antoine Galland's early eighteenth century French translation, which drew partly on oral storytelling rather than a written Arabic source, so even the question of which tales count as original is unsettled.
What would resolve this A complete manuscript stemma tracing every tale's earliest attestation across the Persian, Arabic, Indian and Egyptian branches of the tradition. Comparative philology and codicology have recovered only a partial picture from the surviving fragmentary manuscripts, the oldest of which dates to around the ninth century.
OpenComparative philology and Arabic manuscript studiesOne Thousand and One Nights (Wikipedia)