Ragnall ua Ímair was the grandson of a Viking leader that died in what year?
Ragnall ua Ímair:  He was a grandson of Ímar and a member of the Uí Ímair. Ímar: Ímar (Old Norse: "Ívarr" ; died c. 873) was a Viking leader in Ireland and Scotland in the mid-late ninth century who founded the Uí Ímair dynasty, and whose descendants would go on to dominate the Irish Sea region for several centuries.
i don't know