The explosion of R-M269 descendants who (seemingly) went from zero to a solid majority in much of Western Europe over the last few thousand years is probably one of the most interesting events in recent European history. Not many would have entertained such a possibility until a few years ago, but truth is often stranger than fiction.I would say that this explosion happened post 600 BC. The Syrian G ydna of the sons of Nahor entered Europe sometime after the end of the last European Ice Age (1350 BC but 1500 BC by Velikovsky) which had begun around 1766 BC with the cataclysmic events and worldwide nuclear winter. And this was followed by the Ishmaelite sons of Massa who were the ancestors of the Royal Assyrians (Assir) of I ydna who may have established a secret colony (Asgard) in European Russia from this homeland they descended once more on Assyria as a ruling class and returned to Europe as the Sarmatians (I2). I1 ydna developed from the secret kingdom of Asgard as the future Norse Vikings.
After the fall of the Assyrian Empire the R1a and R1b Israelites left the Samara and Kazan region and were replaced there by the fleeing Royal Assyrians who became the Sarmatians. Odin of the Assir who is said to have lived in the late third century battled with the Vanir (Wends) who were the Parthian Slavs (Voni) of R1a Z283. It was after his defeat by the Slavs that Odin led his people to the north west to Scandinavia. One of the Slav Princes Istemi who married into the Turkish Asena family was the ancestors of the Khazar Kings of Khazaria (R1a Z284).