Are Muslims really unaware that they invaded Christian lands before the Crusades?

that is true, they invade Christian's land when they are suppose to work or live with the Christian peacefully..... this is what makes the Golden Age of Islam end...... they (Muslims) are greed for power and money..... they were suppose to fight if they were attack but they attack on the first time they reach....... I myself a muslims supporter but it is the truth..... misused the word Jihad also cause Islam to fall apart......