I am uncertain about pre-Islamic Persians offering their prayers 5 times day. Is there a copy of that letter online?
Source:
Iran Heritage
From: Shahanshah of Persian Empire, Yazdgird III Sassanid
To: Omar Ibn Al Khatab, Khalifat of Tazi (Persian term for Arabs)
In the name of Ahura Mazda, creator of Life and Intelligence you in your letter wrote that you want to direct us towards your God, Allah, without having the true knowledge of who we are and what do we worship! It is amazing that you occupy the position of Khalifat (Ruler) of Arabs, yet your knowledge is the same as a lowly Arab rambler, roaming in deserts of Arabia and same as a desert tribal man (mardak) you offer me to worship a united and single God without knowing that it has been thousands of years that
Persians worship the mono God and they pray to him Five Times a day! In this land of culture and art this has been the normal path of life for years. When we established the tradition of hospitality and good deeds in the world and we waved the flag of "Good Thoughts, Good Words, Good Deeds" in our hands, you and your ancestors were roaming the deserts, eating Lizards for you had nothing else to feed yourselves and burying your innocent daughters alive (an old Arab tradition because they preferred male children to female). Tazi people have no value for God's creatures! You behead God's children, even the POWs (Prisoners of War), Rape Women, bury your daughters alive, attack the Caravans, mass murder, kidnap people's wives and steal their property! Your hearts are made of stone; we condemn all these Evil which you do. How can you teach us Godly Ways when you commit these actions? You tell me to stop my Fire Worship! Us, Persians see the Love of Creator and power of inventor in the light of Sun and warmth of Fire. Lights and Warmth of the Sun and Fire makes us see the light of truth and warms our hearts to the creator and to one another. It helps us to be kind to one another; it enlightens us and makes us to keep Mazda's Flame, alive in our hearts. Our lord is Ahura Mazda and it is strange that you people also, just discovered him and named him Allah.
But we are not the same as you; we are not in the same level as you. We help other human being, we spread love among humanity, we spread Good throughout the Earth, we have been spreading our culture but in respect for other cultures throughout the whole world for thousands of years, yet you in the name of Allah invade other men's land! You mass murder the people, create famine, fear and poverty for others, you create Evil in the name of Allah. Who is responsible for this entire catastrophe? Is it Allah who commands you to murder, pillage and to destroy? Is it you the followers of Allah who do this in his name? Or is it both? You have risen from heat of the deserts and burnt out infertile lands with no resources, you want to teach people the love of God by your military campaigns and the power of your Swords! You are Desert Savages, yet you want to teach Urban people like us who lived in the cities for thousands of years, the love of God! We have thousands of years of culture behind us, a powerful tool indeed!
Tell us?
With all your military campaigns, barbarianism, murder and pillage in the name of Allah, what have you taught to this Muslim Army? What knowledge have you taught the Muslim that you also insist on teaching it to non Muslim? What culture have you learned from our Allah, now that you want to force-teach it to others? Alas, ...... that today our Persian Armies of Ahura have been defeated from your recently Allah Worshiping Armies; Now, our people have to worship the same God, the same Five times a day, but forced by the sword to call him Allah and pray to him in Arabic because your Allah only understands Arabic I suggest, you and your gang of bandits pack up and move back to your deserts where they are used to live.
Take them back where they used to the burning heat of the sun, tribal life, eating Lizards and drinking Camel Milk. I forbid you to let your band of thieves loose in our fertile lands, civilized cities and our glorious nation. Don't turn these "beasts with hearts of stone" loose, to mass murder our people, kidnap our women and children, rape our wives and send our daughters to Mecca as slaves! Don't let them do these crimes in the name of Allah put a stop to your criminal behavior. Aryans are forgiving, warm, hospitable, and decent people and everywhere they went, they have spread seeds of friendship, love, knowledge and truth; therefore, they shall not punish you and your people for your pirate ways and criminal acts. I beg you to remain with your Allah in your deserts and do not move close to our civilized cities, for your believers are "Much Fearful" and your behavior is "Most Barbaric."
sign,
Yazdgird III Sassanid