From the Old Norse personal name Rögnvaldr (composed of regin ‘advice, decision’ (also, ‘the gods’) + valdr ‘ruler’). This name was regularly used in the Middle Ages in northern England and Scotland, where Scandinavian influence was strong. It is now widespread throughout the English-speaking world.
English: from the Old English personal name Tāta, possibly a short form of various compound names with the obscure first element tāt, or else a nursery formation. This surname is common and widespread in Britain; the chief area of concentration is northeastern England, followed by northern Ireland.