O'Sullivan (Ó Súilleabháinn), the earliest Irish royal family

"The O'Sullivans may be the oldest documented royal family on record. This book explores the history of the O'Sullivans from the time the Gaelic Celts immigrated to Ireland. It examines the archaeological, linguistic and DNA evidence to verify the ancient Irish annals. The book traces six O'Sullivan lines, from the first person called Sullivan, which lead to France, Spain and America"--Cover, page [4].