622 Prophet Mohammad (s) arrived in Medina safely.This is the celebrated Hegira, or Emigration, the traditional
commencement of Islamic history.
- Prophet Mohammad (s) was given a piece of land and had
a house built.
Imam Ali (A) married Fatima (A), who bore him two sons,
Hassan (A) and Hossein (A), and two daughters, Zainab (A) and Umm-i Kulthum (A).
624 A revelation bade Muslims to face Mecca in prayer instead
of Jerusalem.
624 The enlarged house of Prophet Mohammad (s) in Medina was built serving as the primordial mosque of Islam.
Buildings in Arabia were simple structures built of sun-dried mud bricks around a central open courtyard with  porches made of palm tree trunks with thatched roofs of palm fronds. It is generally believed that the house of the  Prophet must have had the same type of plan.
Certain features of this house remained inseparable to all later mosques: the praying space for communal prayer, the  direction of Mecca (the Qibla) so that the worshippers would know which way to face for prayer, and a shelter in the  form of a columned space (hypostyle) to protect the worshipers from the elements.
- The first 18 months after Hegira were spent in settling down.
-Muslims in Medina depended for economic survival on
constant raids on Meccan caravans.
- A small band of men was sent eastward with sealed orders by Prophet Mohammad (s) telling them to proceed to  Nakhla, near Mecca, and attack a caravan from Yemen. The successful raid made Meccans aware of the seriousness of  the threat from Muslims.
-Hassan (A), Imam Ali (A)and Fatima(A)'s elder son, was born. Shias considered him to be the second Imam after Ali  (A).
624 Battle of Badr was fought.
When word of a particularly wealthy caravan, escorted by Abu Sufyan, head of the Umayyad clan, reached Prophet  Mohammad (s), he organized a raiding party of 300 Muslims. Having the wells on the caravan route near Medina filled  with sand, the Muslims lured Abu Sufyan's army to battle at Badr. Despite the superiority of Meccan forces numbering  1,000, the Muslims scored a complete victory, killing many prominent Meccans.
-Battle of Uhud was fought.
Abu Sufyan mobilized Meccan power, and entered the oasis of Medina with 3,000 men on March 21. Prophet Mohammad (s) and his 1,000 men confronted Abu Sufyan's army at the hill of Uhud near Medina. On the morning  of 23 March the Meccan infantry attacked and was repulsed with considerable loss. As the Muslims pursued, the Meccan  cavalry launched a flank attack after the archers guarding the Muslim left flank had abandoned their position. The  Muslims were thrown into confusion. Finally, the battle produced neither a clear victor nor a loser.
625 Mohammad (s) married Umar's daughter, Hafsa.This elevated Umar's status among the Muslims.
-Hossein (A), the younger son of Imam Ali (A) and Fatima(A), was born in Medina. He is revered by Shia Muslims as the third Imam.
- Romans attacked Persia throwing Ctesiphon into panic.
- The Persian king fled.
-Battle of the Ditch, or Khandaq, was fought.
Abu Sufyan led a great confederacy of 10,000 men against Medina. Prophet Mohammad (s) resorted to tactics unfamiliar  to the Muslims who were accustomed to brief, isolated raids. Rather than sally out to meet the enemy in the usual  way, he had a ditch dug around Medina at the suggestion of his military advisor and companion, Salman Farsi. All attempts to cross the ditch failed while the Prophet (s)'s agents among the attackers fomented dissension. A night  of wind and rain' dealt the great Meccan army the final blow and the insurgents melted away. The Prophet (s)'s position was now greatly strengthened.
621 Heraclius entered the Tigris provinces.
628 Khosrow II attempted no resistance, triggering a revolt in which Khosrow II was slain in Ctesiphon by his son  Kavad who replaced him.
This marked the beginning of the end of the Sassanian Empire.
628 Kavad II died and anarchy resulted.
- Heraclius returned the relic of the True Cross to Jerusalem.
628 After a dream, Prophet Mohammad (s) set out on his pilgrimage to Mecca.He and his accompanying followers, about 1600 men, were forced by the Meccans to halt on the edge of the sacred  territory of Mecca, at al-Hudaybiyya. After some critical days the Meccans made a treaty with Prophet Mohammad (s).  Hostilities were to cease, and Muslims were allowed to make the pilgrimage to Mecca in 629.
- Prophet Mohammad (s)'s successful policies were leading more men to become Muslim, and thus his power was growing.
629 An attack by Meccan coalition upon allies of the Prophet (s)led to the condemnation of the treaty of al-Hudaybiyya.
630 Mecca was conquered.
After secret preparations, Prophet Mohammad (s) marched on Mecca with 10,000 men. Abu Sufyan and other leading  members went out to meet him and formally submitted, and Prophet Mohammad (s) promised a general amnesty. When he  entered Mecca there was virtually no resistance. Two Muslims and 28 of the enemy were killed. Prophet Mohammad (s),  who had left Mecca as a persecuted Prophet (s), not merely entered it again in triumph but also gained the 
allegiance of most of the Meccans. Though he did not insist on their conversion, many soon did convert.
After his victory, Prophet Mohammad (s) soon returned to Medina.
- Prophet Mohammad (s) was now militarily the strongest man in Arabia. Most tribes sent deputations to Medina  seeking alliance.
630 Having at first opposed Prophet Mohammad (s), Abu Sufyan submitted to Islam. His daughter, Umm-i Habiba, was married to the Prophet (s). The first Umayyad Caliph, Mu'awiya, was one of his sons.
630 AI-Abbas Ibn Abdul Mutallib (died in 653) half-brother of the Prophet (S)'s father Abdullah, joined Prophet  Mohammad (s).
The later Abbasid dynasty, being descended from his son Abdullah Ibn Abbas, were named after him.
630 Prophet Mohammad (s) pioneered the invasion of Syria, then part of Byzantine Empire.
He took 30,000 men on a month's journey to the Syrian border, and made agreements that set a precedent for treaty  arrangements with captured people.
631 Mohammad (s) chose Abu Bakr to conduct the public pilgrimage to Mecca.
632 Prophet Mohammad (s) personally led the 'farewell pilgrimage' to Mecca, in March. Shias believe that the Prophet (s) unequivocally nominated Imam Ali (A) as his successor while he was returning from 
the 'farewell pilgrimage'to Mecca. Sunnis reject this claim, maintaining that Prophet Mohammad (s) died without  naming a successor.
632 After Ardeshir III and Khosrow III, Yazdgerd III was chosen King.
-Yazdgerd III continued Khosrow' work of collecting the stories of heroes. He appointed Dehghan Daneshvar to update the heroic stories.
He was a senior historian from the imperial court. The term Dehqan was a title that meant 'farmer' as well as  'historian'. He composed Khodaynameh in New Pahlavi language. It consisted of all the heroic tales from the time of  Kiyumars to Khosrow II. It became the main source for the future books of Shahnameh.
632 Prophet Mohammad (s) passed away in Medina in June. Rashidin Caliphs succeeded Prophet Mohammad (s). Under the  Caliphs, Muslim armies brought the new faith to the world. Meanwhile, the 5assanians had suffered a recurrent series of crises. Centuries of foreign wars and struggles had  exhausted them. The empire had expanded and so had the bureaucracy. The central authority of 5assanian court had 
declined in favor of its generals, who were now ruling the empire. Due to internal crisis, there was no army  powerful enough to resist enemy onslaught. The Sassanian administration was about to fall victim to the highly  inspired Muslims.
632 Prophet Mohammad (s)'s death thrust the young Muslim community into a protracted debate over the criteria of  legitimate succession.
- Two predominant solutions to the problem of succession emerged. One group maintained that the Prophet (s) had  explicitly designated his son-in-law Ali (A) as his successor. The other, convinced that Prophet Mohammad (s) had  made no such appointment, opted for consensus to choose from among a group of elder companions of Prophet Mohammad  (s). They chose Prophet Mohammad (s)'s father-in-law Abu Bakr as the first Khalifat Rasul Allah ("Successor of the Prophet of God") while Ali (A) was attending the last rites of the Prophet (S).
- The group that supported Imam Ali (A)'s candidacy came to be called the Shi'a, "party" or "supporters" of Imam Ali (A). Those who backed Abu Bakr were in the majority and formed the nucleus of what became known as "People of the Sunna and the Assembly", Sunnis for short.
- Abu Bakr assumed the Prophet (S)'s political and administrative functions, thereby initiating the office of Caliphate.
632 Ali (A) did not submit to Abu Bakr's authority for some time. Nor did he actively assert his own rights, possibly because he did not want to throw the Muslim community into bloody tribal strife.
Imam Ali (A) retired into a quiet life in which religious works became his chief occupation. The first chronologically arranged version of the Qur'an is attributed to him, and his excellent knowledge of the Qur'an and Hadith aided the first three Caliphs in legal problems.
632 Abu Bakr set out to suppress the tribal political and religious uprising, bringing central Arabia under Muslim control.
632 Abu Bakr began the Muslim conquests by undertaking direct expansion from Arabia into Iraq and Syria.
633 Fatima (A), Prophet Mohammad (S)'s daughter and Imam Ali (A)'s wife, passed away in Medina.
633 The Muslims led by Khalid Ibn Walid launched their first successful incursion on Persia and the defeat was decisive.Town of Hira surrendered to the Muslim forces.
633 After a succession of short-time rulers, Yazdgerd III,grandson of Khosrow II, came to the throne.
- The prolonged and exhausting hostilities between Persia and Byzantium had drastically reduced the powers of both of these empires.
634 Umar, nominated by Abu Bakr, took his place at the helm of Islam.
Umar's reign saw the transformation of the Islamic state from an Arabian principality to a world power. Under Umar, Muslim armies conquered Mesopotamia and Syria and began the conquest of Persia and Egypt.Muslim troops pushed toward Syria and Byzantium surrendered.Army commander Abu Ubaida was defeated in a battle against the Persians.
635 Muthni Ibn Haritha defeated the Sassanians in the third battle.
636 Sa'd Ibn Waqqas severely defeated the Persians at the battle of Qadisiyya.
- Commander Rostam Farrokhzad was killed at the battle of Qadisiyya.
637 Low lands of Iraq submitted to the Muslims.Commander Hormozan resisted for 21 years in Ahvaz and Shushtar.
638 Ctesiphon fell to the vigorous Muslim campaign. 640 Mu'awiya was appointed governor of Damascus by Caliph  Umar.
641 Luqman Ibn Muqran commanded the invading forces at Nehavand, western Persia.
- Sassanians were decisively defeated at the battle of Nehavand.
642 Yazdgerd III was defeated and his heirs fled to China. The splendid and gigantic edifice of the Sassanians crumbled to pieces. Within a decade, the Sassanian rule came to a close.