Brian, surely you can't be surprised? Byzantine history is a gaping void in the general knowledge of most people, for perhaps understandable reasons. The state itself is extinct, sadly, and the West/Latins/Catholic Church committed, arguably, one of the most stupid mistakes in history by conducting the Fourth Crusade against it.
It's a shame, but not surprising. The Romans are held up as the pinnacle of civilisation, and the Byzantines fall between the stools of Ancient Rome/Greece on the one hand and medieval England/France on the other.