The story of Roland was used to promote the importance of the Crusades. It was written around 1100 A.D, and followed the story of young Count Roland as he fought in Charlemagne's army against the Muslims in France.
Roland and his friend, Oliver are picked to lead a small group of soldiers as the rear guard behind the main army. What they don't know however, is that a traitor of Charlemagne has given away information to the Muslims. Unbeknownst to them, a surprise attack is planned on the army of Roland and Oliver.
Oliver insisted that Roland blow the trumpet to warn King Charlemagne about the attack so that he could come and deliver them; because they were sorely out-numbered. Roland, however insisted that to do so would be detrimental to their military pride and glory. He finally won the argument, and the trumpet was not blown. Even when defeat seemed certain, Roland would not retreat. He didn't want anyone to remember him as a coward, but as a hero.
– Roland is worried about ruining his reputation by blowing the horn. He does not want anyone to believe that he is a coward who needs help fighting off the enemy.
– Roland also does not want his country of France to be shamed. He thinks that sounding the horn would be detrimental to France's honor and pride. He doesn't want people to believe France is full of cowards who are unable to win a battle.
– He does not want to give the Muslims the satisfaction that he was scared and had to blow his horn for help. He doesn't want that action to reflect badly on his country.
Oliver wants military victory; that is his goal. He feels that winning is the whole point of battle. That is what you look towards, and you try to achieve it any way possible. Even if that means blowing the horn to bring backup. Roland on the other hand, wants to preserve military honor and pride. He is not interested in just winning; to him, no matter the outcome of the battle he wants to maintain his good appearance. Roland knew that he would lose the battle if he did not call for help, but to him losing and dying was worth preserving his military figure as a courageous leader.