Southern Anatolia was colonised early by Neolithic farmers from the Near East (E + J2).
The Indo-European invasions brought the Hittites (1750 BCE), the Lydians and Lycians (1450 BCE) and theProto-Armenians (1200 BCE). All were probably R1b, considering the high percentage of R1b in the regions they settled. R1b Indo-Europeans are thought to have originated on the north-eastern shores of the Black Sea, just north of the Caucasus. They could have invaded northern Anatolia by crossing the Caucasus, sailing across the sea, or going around via the steppes through the Bosphorus.
Later R1b were possibly (part of) the Sea Peoples that ravaged the ancient Near Eastern civilizations, from Greece to Egypt. Their advance military technology and sea-based culture make of them very good candidates.
The Phrygians arrived in northern Anatolia after 1200 BCE, and were probably an offshoot from the Thracians (so R1a).
The Cimmerians are probably the last wave of migration (around 700 BCE) from the R1b homeland. They are said to have be expelled from Anatolia and moved to Europe, where they joined the other R1b people. Germanic and Celtic people both claim (partial) Cimmerian ancestry.
Romans, Celts and Germans
Celtic, Italic and Germanic people are all descended from the same R1b1b2 stock. They split north of the Alps.
The Italic branch went south and mixed with the Terramare people who were I2a, G2a and E-V13. Northern Italians have more Indo-European Celto-Italic blood, while southern Italian have more indigenous blood (the highest being Sardinia, then Basilicata).
The Germanic branch moved north and mixed with the indigenous I1 and I2b people, who had already mixed with R1a migrants from the Corded Ware (Battle Axe) culture. The new hybrid Germanic people retained the highest percentage of aboriginal haplogroup I.
Celtic people split in several groups : the Brythonic went to Britain and Ireland, the Gaulish to France, the Iberian to Spain and Portugal, and the Alpine remained around Austria, Switzerland, southern Germany, Eastern France and Belgium. The Iberian and Gaulish groups mixed with I2b, I2a and E people, the Alpine with I2b and E, and the Brythonic just with I2b people.
It is likely that the language of the aboriginal Europeans influenced the various Celtic, Italic and Germanic dialects. Germanic languages diverted the most from the original European R1b language because it assimilated a very large part of aborigines.
From about 700 BCE, the Etruscans settled around Tuscany and the Greeks in southern Italy. Etruscans probably came from Palestine and brought haplogroups J1, J2 and E with them. The Greeks in Italy were Doric and brought J2, E, G2a and probably more R1b (see above). The Romans progressively absorbed the Etruscans and Italian Greeks and mixed with them. By the time of Julius Caesar Roman citizens were probably composed of 45% of R1b, 20% of J, 15% of E, 15% of G2a and 5% of I2a.