This, most probably is fiction, but the argument is sufficiently thought provoking.
From: Omar Ibn Al Khatab Khalifat Al Muslemin To: Yazdgird III Shahanshah of Persian Empire
Yazdgird, I see not a fruitful future for you & your nation unless you accept my offer & commit Bei’at (Joining with Khalifat & bringing Islam). Once upon a time your land ruled half the known world but what has it come down to now? Your troops are defeated in all fronts & your nation is bound to collapse. I offer you a way to rescue yourself. Start praying to a mono God, a single union God, the only God who created everything in the universe. We bring you & the world his message, he who is the true God. Stop your Fire Worship, command your nation to stop their Fire Worship which is false; join us by joining the truth. Worship Allah O Akbar the only true God, The creator of universe. Worship to Allah & accept Islam as your salvation. End your Pagan ways & your false worships now & bring Islam so you can accept Allah O Akbar as your savior. By doing so, you will find the only way to your survival & peace for Persians. If you know what is best for Ajam (Arabic term for Persians meaning Retarded & Weird), you will choose this path. Bei’at is the only way.
Allah O Akbar sign, Khalifat Al Muslemin Omar Ibn Al Khatab
And here is Yazdgird III, famous respond to Omar:
From: Shah of Shahs, Shah of Persia and Beyond, Shah of many Kingdoms, Shah of Aryans and Non Aryans, Shah of Persians and many other races as well as Arabs, 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 & Intelligence,
You in your letter wrote that you want to direct us towards your God, Allah O Akbar, without having the true knowledge of who we are & 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, & same as a desert tribal man!
“Little Man” ( mardak) you offer me to worship a united & single God without knowing that it has been thousands of years that Persians worship the mono God & they pray to him Five Times a day! In this land of culture & art this has been the normal path of life for years.
When we established the tradition of hospitality & good deeds in the world & we waved the flag of “Good Thoughts, Good Words, Good Deeds” in our hands, you & your ancestors were roaming the deserts, eating Lizards for you had nothing else to feed yourselves & burying your innocent daughters alive (an old Arab tradition, cause 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 & 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 action?
You tell me to stop my Fire Worship! Us, Persians see the Love of Creator & power of inventor in the light of Sun & warmth of Fire. Lights & Warmth of the Sun & Fire makes us see the light of truth & warmens our hearts to the creator & to one another. It helps us to be kind to one another, it enlightens us & makes us to keep Mazda’s Flame, alive in our hearts. Our lord is Ahura Mazda & it is strange that you people also, just discovered him & named him Allah O Akbar! 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 & poverty for others, you create Evil in the name of Allah. who is responsible for all this catastrophe?
Is it Allah who commands you to murder, pillage & 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 & burnt out infertile lands with no resources, you want to teach people the love of God by your military campaigns & 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 & pillage in the name of Allah O Akbar, 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 your Allah, now that you want to force-teach it to others?
Alas, Oh 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 & pray to him in Arabic, cause your Allah only understands Arabic!
I suggest, you & your gang of bandits pack up & 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 & drinking Camel Milk. I forbid you to let your band of thieves loose in our fertile lands, civilized cities & our glorious nation. Don’t turn these “beasts with hearts of stone” loose, to mass murder our people, kidnap our women & children, rape our wives & send our daughters to Mecca as slaves! Don’t let them do these crimes in the name of Allah O Akbar, put a stop to your criminal behavior.
Aryans are forgiving, warm, hospitable, & decent people and everywhere they went, they have spread seeds of friendship, love, knowledge & truth; therefore, they shall not punish you & your people for your pirate ways & criminal acts.
I beg you to remain with your Allah O Akbar in your deserts & do not move close to our civilized cities, for your believes are “Much Fearful” & your behavior is “Most Barbaric”!
Yazdgird III Sassanid