The opening scene to Hamlet is a bit...ghostly! Specifically, men are keeping guard over the castle of the King of Denmark. One man, Francisco, leaves his shift, and the guard Bernardo discusses whether the "ghost" has $($again$)$ appeared throughout the night with two other men$--$Horatio and Marcellus. Just then, the ghost appears. The men comment that the ghost looks like the old king who died $($whose name was also Hamlet$).$ The men know it to be the king because "Such was the very armor he had on $/$ When he the ambitious Norway combated" $($lines $60-61).$

The question: At the bottom of page $1714,$ the men ask Horatio to tell what he knows of what happened between Old King Hamlet and Norway $($the Old King of Norway, named Old Fortinbras$).$ What is it that Horatio says happened between these old dead kings?