I’ve never been fond of it, never made a lot of sense, actually, but since they were good at business, the “byz’ part is easy to remember. ;’)
Their last really kick-ass ruler was Boris the Bulgar-slayer; this page about him damn near mede me wet my pants when I read it.
http://www.badassoftheweek.com/basil.html
He rocked!
I shake my head at how his successors blew it.