The sun shines over Saharan dunes. A millennium (pl millennia) is a period of Time equal to one thousand Years (from Latin la mille, thousand and la annum The 4th millennium BC saw major changes in human culture It marks the beginning of the Bronze Age and of Writing. A century (from the Latin centum, meaning one hundred is One hundred consecutive Years Centuries are numbered ordinally (e Cultures c 3400 BC — Sumerian temple record keepers redesign the Stamp seal in the form of a cylinder Events c 3150 BC — According to the legend Narmer ( First Dynasty) started to rule in Ancient Egypt. See also List of centuries, History This is a list of Decades in history including links to corresponding articles with more information about them