In the Old English epic poem Beowulf, why did Hrothgar build Herot?

Beowulf, an Old English epic poem, was written somewhere around 600-900 A.D. It is the oldest known major work in Old English. It's author is unknown.
Much of the action takes place in a mead hall called Herot that was built by theDanish king, Hrothgar. The poem spends a great deal of time describing Herot and how it was central to the lives of the warriors. Hrothgar's motivation for building Herot is given in the first chapter (of the Burton Raffel version) of the poem:

Then Hrothgar . . . resolved
To build a hall that would hold his mighty
Band and reach higher toward Heaven than anything
That had ever been known to the sons of men.

Hrothgar wants Herot to serve several purposes. He wants to create an atmosphere of fellowship for his warriors. Kings in those days treated their key warriors respectfully, often rewarding them with gold for their efforts. Herot was actually made with some gold on the inside, so it helped foster a sense of loyalty in his men.
As the excerpt states, there is also a religious component at work here. Hrothgar wanted Herot to “reach higher toward Heaven.” Herot is a way for Hrothgar and his men to feel that they are more connected to God than they would be otherwise.