King Khosrau II, technically the last King of Sassanid Empire, in 628 A.D., was murdered along with 18 eligible male heirs to the throne in a coup led by his son, Shiroye. Shiroye, the new king, did not last long. He died of plague within a year of accession. In fact, the death of Khosrau II was the last straw to wipe a grand civilization off the face of the earth. It never rose from the ground again.
Khosrau II, the victorious, is said to be brave, wise, forethoughtful and unmatched in military might. However, the epithets attributed to him seem cynical, as he was totally blind to the devastating developments taking place in the deserts of Arabian Peninsula, a neglect that, after 1392 years, still continues to threaten the life of not only the victimized Persians but also the life of the entire world.
From 628 A.D., the year King Khosrau II was murdered, up to year 632 A.D., that is, just four years, his son, the murder, and 10 baby kings plus Khosrau II's grandson Yazdegerd III, or rather Shiroye's son, succeeded King Khosrau II, but none could save the tailspinning empire. Yazdegerd III is said to be an illegitimate son of Shiroye. King Khosrau II, on advice of his astronomers, was told that Shiroye's son would, if born, betray the empire. Khosrau II had ordered his son not marry anyone in order to prevent the curse, but Shiroye went to bed with a slave or commoner and thus Yazdegerd III was born.
From 621 until 632, Arabian Peninsula was engaged in an ideological civil war between newly emerged Islamists of 1400 years ago and the majority of Arab citizens who preferred to keep their ancestors' faith. After several bloody battles, lasting 10 years, Islamists were able to enforce their new ideology. Mecca, capital and home to their place of worship, called Kaaba, was captured.
Anyway, four years after the demise of Khosrau II , that is, 632 A. D., a new Islamist ruler had just assumed power in Arabian Peninsula when many Arabs revolted against the new successor, but the new ruler refused to grant their wishes. Many died. These battles are called 'Ridda' or apostasy.
However, the 2nd ruler worked out a clever strategy, that is, diverting the attention of his fierce fighters to neighboring countries, namely, Persia, where there were everything to get: treasures, beautiful women, handsome boys to be used as sex tools. "What are you waiting for?" was the ruler's message to his fighting men.
The bandits poured out under the command of brilliant commanders and headed toward Persia, the land of a people who already believed in an ethically superior god, a god that emphasized on moral choice. However, the 2nd ruler's army delivered devastating blows on Persians who had taken them to be heralds of peace and not vicious bandits. The savage bandits captured the capital of Sassanid Empire, Ctesiphon, in present Iraq. Briefly, Persians failed to stop the Arab invaders. In 634, this 2nd ruler fell sick and died. And the 3rd ruler assumed power.
The 3rd ruler's generals were able to flatten the entire Sassanid Empire, 6,600,000 km² in width, extending from Turkey, on the West and Central Asia, on the East. POWs and ordinary males were beheaded in front of their families. All young females and under age boys were taken as sex tools or taken to slave markets as infidels, including the female courtiers.
Bandits continued their total destruction on a daily basis. In 650 A.D., that is 18 years after the fall of Ctesiphon, the Arab forces reached Sistan, near the border of Afghanistan, about 2,306 km, away from Baghdad. According to a local historian, "Rabi' ben Ziad, the head of Arab invaders, set up a huge platform of people he had killed in Sistan, covered by cloth, and stood upon it to meet the delegation of the region, Iran ben Rustam, the head of Sistan province. Rabi' was tall, dark, and very ugly with horsey teeth and large protruding lips. Iran ben Rustam, a Zoroastrian, seeing him, whispered to his companion, "I'll be damned! We were told devil does not show up in broad daylight, but there he is standing on the heap of corpse." Rabi', the missioner of Islam, who could not understand Persian, demanded translation. After hearing the translation, he triumphantly laughed. Iran ben Rustam spread a clean rug on the ground and sat down to negotiate with the messenger of the new faith. Iran accepted to deliver to the Arab conqueror 1,000,000 Persian Drachma plus 2000 under puberty boys, as sex tools, etc. to spare the life of the still alive people of the region.