The interaction between the Illyrians and the Slavs was a love-hate relationship and has remained so ever since. Some Illyrian groups assimilated, intermarried and assumed the culture of the invaders. In 300 years, between the 6th and the 8th centuries AD, all the Illyrians in today's former Yugoslav republics vanished only to re-appear as Slavs. But the Illyrians of the south (Albania, Western Macedonia) resisted this process of dilution bitterly and preserved their identity and culture fiercely. To distinguish themselves from the "assimilated" - they invented Albania. The name itself is much older. Ptolemy of Alexandria mentioned it 600 years before the Illyrians began to apply it to their dwindling polity. And another 300 years were needed - well into the 11th century AD - before the Illyrians were fully accepted their reinvention as Albanians - the successors to the Albanoi tribe, which used to occupy today's central Albania (formerly called Arberi). Five centuries later, the Albanians themselves renamed their territory and began to call it Shqiperia. No one really knows why, not even Albanian scholars, though they like to attribute it (on flimsy etymological grounds) to Shqipe, the Albanian word for Eagle. Thus, Albania was transformed to the Land of the Eagle. It is an irony of history that the Middle (or Dark) Ages were the best period ever in Albania's history. Powerful cities proliferated, inhabited by a class of burghers who engaged in trading. Albanian merchant houses established outposts and branches all over the Mediterranean, from Venice to Thessalonica. Albanians were the epitome of education and cultivated the arts. They conversed only in Greek and Latin, letting the auld language die. The Byzantine Empire was divided to military provinces (themes). One thing led to another and military commanders transformed feudal lords administered serfdom to the population. Feudalism co-existed and then supplanted urbanism and the big estates became so autonomous that they ignored the Byzantine court altogether.