Act 1, Scene 1

What happened? Whose fault was it? Who started the fight? Any punishment?

The fight between the Montague family and the Capulet family was so meaningless, petty and frivolous, as whe know that the two families are a great enemies for lots of years. But it is still not right to fight in the streets.
The main thing is the Capulet family who started the fight first. The evidence is that Sampson provoke the Montague's servant first. Sampson said that he will make a rude face at Montague's servants and make them angry, it tells us that it was Sampson who started the fight first and also Sampson's fault.
After that, before anything happens, Balthasar and Abram arrived, Gregory the Capulet's servant, asked Sampson to take out his sword and start to fight.
As whe know that Benvolio wants to make a peace with them, Tybalt the Juliet's cousin does not like the word of "peace", because of Tybalt, Benvolio and Tybalt started to fighting too with each other, more and more people joined to fight
Finally, the Prince stopped them to fight and he said to the Capulet family to come with him and the Montague family come and see him later. I think there is no punishment for them.

Romeo's love life

Romeo is the son to Lord and Lady Montague. The play opens with the servants of the Montague and Capulet families quarreling and fighting in the streets of Verona, Italy. The two families have been enemies for as long as anyone can remember. Romeo, son of Lord Montague, accidentally finds out about a ball given by Lord Capulet and plans to attend uninvited. Romeo attends the ball at the Capulet house in hopes of meeting Rosaline ( the girl that romeo loves so much). Romeo and his friends Mercutio and Benvolio put on masks and attend the ball, and there Romeo meets the beautiful girl, more beautiful than Rosaline, and her name is Juliet and Romeo falls instantly in love.

Romeo's family

Montague is the patriarch of the house of Montague.
Lady Montague is the matriarch of the house of Montague and she was Romeo's mother.
Lord Montague is the father of Romeo
Romeo is the son of the Montagues, and is the play's male protagonist.
Benvolio is a cousin, and friend, of Romeo.
Abram and Balthasar are servants of the Montague household.