Ancient Egypt emerged as a unified civilization around 3150 BC when Upper and Lower Egypt were united.
Notes on verification
Multiple independent academic and historical sources consistently confirm both the unification event and the approximate date of 3150 BC. Minor variations in exact dating (3150-3100 BC) are typical for events of this antiquity and don't undermine the core claim. The attribution to King Narmer/Menes is well-established in Egyptology.
Sources
- Ancient Egypt (wikipedia)