King Lear has given up his kingdom because he is old and wants to be free to enjoy himself in retirement for the remainder of his life. He has specified that he will live with his two daughters alternately and will retain a following of one hundred knights. Early in Act 1, Scene 3, Goneril confides to her steward Oswald that she is getting sick and tired of having her father and his hundred knights making a playground of her household and domain.
By day and night he wrongs me; every hour
He flashes into one gross crime or other,
That sets us all at odds. I'll not endure it:
His knights grow riotous, and himself upbraids us
On every trifle. When he returns from hunting,
I will not speak with him; say I am sick:
If you come slack of former services,
You shall do well; the fault of it I'll answer.
At this point the stage directions read "Horns within." By "within" is meant "offstage." This is not to show that the King is being greeted with a fanfare but to underscore Goneril's complaint about her father's and his knights' riotous behavior--and we can imagine her body language when she hears those horns. She stiffens, clenches her fists, and grits her teeth. She is getting to hate those hunting horns which seem to exemplify the carefree, inconsiderate behavior of her unwelcome guests who have nothing to do but go hunting every day and then come back on their hundred and one horses with muddy boots and a lot of bloody carcases to drink and carouse all night. The King is having the time of his life, but he doesn't realize what a bad impression he is making in this household because he has always done just as he liked. In addition to his other faults, he and his men must be killing all the game for miles and miles around.