Robyn Hardyman 
Forgotten Kings and Kingdoms [PDF ebook] 

Many people are fascinated with the great kingdoms and rulers of the distant past. For some, no records survive to prove their existence. For others, the records are woven with so many fanciful details they seem like legends. Be a mystery hunter, find out more about the lore and history of familiar legends around the world, and use all the evidence to decide what you believe.