1,428 years ago, a tribe of Arabs named Tazi with no identity and no culture lived in the desert of Arabia.
They would not trust each other living in the desert with no water or food.
If five of them slept together in a tent (kheymeh), four wouldn't make it alive the next day.
They would regularly kill each other over a little food or possessions.
Before attacking and invading the comparatively, wonderful heavenly region of Iran, their barbaric leaders set about patching up the internal unrest between hungry tribes by promoting and saying "Salam" and "Salam-ol-Aleykom" to each other meaning "Truce" in other words "Don't kill me, I am on your side".
At the same time, Iranians with more than 8000 years of history and culture living with philosophy of their great teacher Zartosht who never assumed prophethood or said that he had been missioned to bring any message from God to human beings, believed in good thoughts, good words and good deeds.
They lived in communities and peace;
enjoyed life and promoted happiness;
lived healthy and long life;
shared wealth and cared for one another;
celebrated 365 days a year
including Norooz, Mehregan, Shabe Cheleh, Sadeh, and above all to greet each other they would say: "Dorood" meaning "Wishing you well, health, and happiness".
Dorood = Wishing you Well, Health and Happiness
Salam = Truce / Peace (Don't kill me!)