Actually, Rome was "saved" a couple of times by folks the elites thought of as "barbarians". The "barbarians" worried greatly that Rome was going to the dogs.
In 538 AD the Western Roman Empire went down for the last time. The Dark Ages began that spring, and lasted, more or less, for another millenium. The Eastern Roman Empire stayed in business.
A.D. 538? What happened in that year? I think you may mean 568 (beginning of the Lombard conquest of Italy). Between 535 and 554 Justinian I reconquered Italy from the Ostrogoths. He had earlier retaken North Africa, and also managed the reconquest of a small part of Spain. North Africa wasn't lost to the Arabs until the very end of the 7th century, and bits of Italy remained under Byzantine control until 1071.
One of the names Theodore Roosevelt called Woodrow Wilson in 1915 (when he refused to ask for a declaration of war after the sinking of the Lusitania) was "Byzantine logothete." Western Europe may have been relatively backward and uncivilized during the Dark Ages, but at least they didn't have no steenking logothetes.