In Romeo and Juliet, what causes Tybalt's anger and what does he intend to do? Why does Lord Capulet stop him?

Tybalt, a Capulet, recognizes Romeo's voice (even though his face is hidden by a mask) at his uncle's ball. He is outraged that Romeo would appear at his uncle's home, and is determined to kill him, telling his servant to get his rapier. Capulet, despite being the enemy of the Montague, forbids Tybalt to do so, first because he is under his roof, and second because he has heard that young Romeo is a "virtuous...

Tybalt, a Capulet, recognizes Romeo's voice (even though his face is hidden by a mask) at his uncle's ball. He is outraged that Romeo would appear at his uncle's home, and is determined to kill him, telling his servant to get his rapier. Capulet, despite being the enemy of the Montague, forbids Tybalt to do so, first because he is under his roof, and second because he has heard that young Romeo is a "virtuous and well-govern'd youth". Tybalt protests, and Capulet insists that Romeo is not to be touched. This is a pivotal event in the play in more than one way. Capulet's forebearance allows his daughter to meet Juliet, and Tybalt's rage and hatred for Romeo will eventually lead to their disastrous duel in the streets. Given that the Chorus has already told the audience that Romeo and Juliet are to die, they can perhaps surmise that this event will have grave consequences.