 For example, Eyvindr skáldaspillir composed in the latter half of the 10th century, and he uses a couple of lines in his "Hákonarmál" that are also found in "Hávamál".It is possible that he was quoting a known poem, but it is also possible that "Hávamál", or at least the strophe in question, is the younger derivative work.The few demonstrably historical characters mentioned in the poems, such as Attila, provide a "terminus post quem" of sorts.