Richard Wilbur's poem "Beowulf" was a take on the original Anglo Saxon epic Beowulf. In his poem, he is trying to say that the Danes and Geats didn't' know why Beowulf should save the Danes from their terrible fate.
Until the monster's death, the people of the Danes lived in an oblivious state of happiness. This made them seem "...strange, were strangely warm." They lived in a time where killing one another was honorable and held much glory. Then, Beowulf came into this country and put a stop to these murderous actions. The people of the land didn't have to hide behind this mask of being nice to excape the prevalent reality of death anymore. They became "...strange, the people were strangely warm."
The noble Geat received riches of all sorts, but he didn't' want them. All he wanted was a son to pass down his legacy. He saved the Danes from themselves so they would have sons and wouldn't become extinct, like they were sustained to be. Beowulf soon died thereafter in his own country and without a son. The people of the nation tried to morn for him, but, they didn't understand why this hero rescued them. They still may not know why, but the Danes are here today.