Symbols are objects, characters, figures, or colors used to represent abstract ideas or concepts.
Like most of Shakespeare’s other history plays, 1 Henry IV does not make great use of symbolism as a literary device: the play concerns real people and events and so tells a much more concrete story than a more symbolic play like Macbeth or The Tempest. The most important symbols, generally speaking, are the characters themselves, and what they represent is simply the set of ideas and traits with which they are involved. Glyndwr represents both the Welsh motif in the play and the motif of magic, while Hotspur represents rebellion and the idea that honor is won and lost in battle.
The sun in 1 Henry IV represents the king and his reign. Both Harry and his father, Henry, use an image of the sun obscured by clouds to describe themselves—the former in Act I, scene ii, lines 175–181, and the latter in Act III, scene ii, lines 79–84. For King Henry, the clouds that blur his light come from his own doubts about the legitimacy of his reign. For Harry, these clouds are the shades of his immaturity and initial refusal to accept and adopt his noble responsibilities. Having accepted his royal duties, Harry can anticipate shining through these clouds and radiating his full regal glory.