The second period is called by Muḥammadan writers the _Jáhiliyya_, _i.e._, the Age of Ignorance or Barbarism.[17] Its characteristics are faithfully and vividly reflected in the songs and odes of the heathen poets which have come down to us. There was no prose literature at that time: it was the poet's privilege to sing the history of his own people, to record their genealogies, to celebrate their feats of arms, and to extol their virtues. Although an immense quantity of Pre-islamic verse has been lost for ever, we still possess a considerable remnant, which, together with the prose narratives compiled by Moslem philologists and antiquaries, enables us to picture the life of those wild days, in its larger aspects, accurately enough. [Sidenote: The Moslem Arabs.] The last and by far the most important of the three periods comprises the history of the Arabs under Islam. It falls naturally into the following sections, which are enumerated in this place in order that the reader may see at a glance the broad political outlines of the complex and difficult epoch which lies before him. _A._ The Life of Muḥammad. [Sidenote: Life of Muḥammad.] About the beginning of the seventh century of the Christian era a man named Muḥammad, son of ‘Abdulláh, of the tribe Quraysh, appeared in Mecca with a Divine revelation (Koran). He called on his fellow-townsmen to renounce idolatry and worship the One God. In spite of ridicule and persecution he continued for several years to preach the religion of Islam in Mecca, but, making little progress there, he fled in 622 A.D. to the neighbouring city of Medína. From this date his cause prospered exceedingly. During the next decade the whole of Arabia submitted to his rule and did lip-service at least to the new Faith. _B._ The Orthodox Caliphate (632-661 A.D.). [Sidenote: The Orthodox Caliphs.] On the death of the Prophet the Moslems were governed in turn by four of the most eminent among his Companions--Abú Bakr, ‘Umar, ‘Uthmán, and ‘Alí--who bore the title of _Khalífa_ (Caliph), _i.e._, Vicegerent, and are commonly described as the Orthodox Caliphs (_al-Khulafá al-Ráshidún_). Under their guidance Islam was firmly established in the peninsula and was spread far beyond its borders. Hosts of Bedouins settled as military colonists in the fertile plains of Syria and Persia. Soon, however, the recently founded empire was plunged into civil war. The murder of ‘Uthmán gave the signal for a bloody strife between rival claimants of the Caliphate. ‘Alí, the son-in-law of the Prophet, assumed the title, but his election was contested by the powerful governor of Syria, Mu‘áwiya b. Abí Sufyán. _C._ The Umayyad Dynasty (661-750 A.D.). [Sidenote: The Umayyad dynasty.]