What is the cause of conflict between Oliver and Orlando?

We do have evidence why Oliver hates his youngest brother Orlando. From the very beginning he is very jealous of the noble qualities of his brother that people praise. So he wants to be the one to be praised and is so cruel and selfish that he deprives him of all education, inspite of his father writing in his will that Orlando should be brought up with a noble upbringing. Still Orlando grows up to be a perfect gentleman like his father.

When Orlando comes to know of the will by his faithful servant Adam, he is angered and says that his tolerance has vanished, he can no longer bear this tyranny. On the other hand Oliver decides to put an end to Orlando's demands once and for all by killing him. This is the cause of the conflict. He thinks of various ways to do this.

Later on he employs the strongest wrestler in the town, Charles, to kill his brother. But Orlando defeats him too. (It is here that he meets Rosalind). This angers Oliver all the more and plans to set fire to Orlando's lodge while he's asleep. Thus the conflict continues.