Hi Anton. There are many theories regarding the origin of PF5456. There is an interesting paper, published on May 2018 by Nature, that gives some solid arguments regarding the mother clade of PF5456, CTS3601, ''A finely resolved phylogeny of Y chromosome Hg J illuminates the processes of Phoenician and Greek colonizations in the Mediterranean''.
Analyzing ancient alleles, they said that Branch 59 (CTS6061), as a subclade of L397 (L70), has an ancient origin in continental Greece, and that afterwards moved to southern Italy, with the founding of greek colonies, about 2.700 years ago ( more or less), becoming PF5456, and it's clades. Probably on roman times, it moved from the italian peninsula to the rest of Europe, and elsewhere, withe the expansion of the Roman Empire.