Julian II (the Apostate) and his policies

[Robert Vermaat]

And he successfully incorporated into the Empire some of the tribes that

Which one?? He just give up al the work his father had done!

I don't know who you're quoting here, but he's right. Julian srttled the Franks who had overrun Germania II succesfully in northern Gaul. These Franks were never troublesome again, defended the borders where they lived and a hundred years later took over when the Roman administration finally fell apart. Their wish to emulate the Romans means that French is now spoken in France, not German and Celtic.

Whose father do you mean? Julian's? What work did he actually do?
Julius Constantius was the son of Theodora and her husband Constantius I , and the half-brother of the Emperor Constantine I. He seems to have spent his youth under house arrest in Tolosa, and later in Corinth. Constantius did not outlive brother Constantine by much because he perished in the imperial purges of 337. So what work are you referring to?

And Constantines dynasty succesfull? In what way? Producing 3 sons and give them each a share so they can battle each other?

Fact is that the Romans never had a constitutionalized form of transfer the power from the dead ruler to the new ruler and that was the big problem!

Oh, we agree there! Constnatine's dynasty may have been suucessful in changing tghe face of Late Roman society (introducing and strengthening Christianity helped post-Roman Europe a lot later on), but the seeds of destruction were there as well - the purge of 337 killed most of the family off, and child emperors became the root of much evil when, instead of adoption of strong sons, the troops demanded a dynastic line, even though such weaklings like Honorius or Valentinian III became emperor! In the end, these weakling gave rise to strong men behind the throne, Romans, euneuchs then, barbarians later. And what had to follow did of course follow - at one point the powerless figurehead called emperor was sent home to his mommy, and the generalissimo became to first post-Roman king. Exit Western Empire.