It was here that he fell in love with al-Khayzuran (translates as "bamboo"), a daughter of a warlord in Herat[3] and had several children, including the fourth and fifth future Caliphs, al-Hadi and Harun al-Rashid.

Mahdi commenced his rule by releasing several political prisoners, expanding and decorating the holy places of Mecca and Medina, and building fountains and lofts for Hajj pilgrims.

Tarath was so pleased with the hospitality he received that he offered to put his engineering knowledge to use and build a mill that would generate annual profits, of 500,000 dirhams, equal to the cost of its construction.

[10] While the first Abbasid caliphs were distracted with cementing their authority, the Byzantines were occupied fighting Slavic clans in Macedonia and Thrace and battling the Bulgars.

[11] His son Harun would also pursue similar policies, releasing many of the Umayyads and 'Alids his brother Al-Hadi had imprisoned and declaring amnesty for all political groups of the Quraysh.

[36] In 778, the Byzantines, under Michael Lachanodrakon, seized the town of Germanikeia (Ma'rash), where they captured significant amounts of booty and took many Syrian Christians captive, and defeated an army sent against them by the Abbasid general Thumama ibn al-Walid.

[37][38][39] In the next year, the Byzantines took and razed the fortress city of Hadath, forcing Caliph al-Mahdi (r. 775–785) to replace the rather passive Thumama with the veteran al-Hasan ibn Qahtaba.

His son and heir Harun—better known by his laqab, or regnal name, al-Rashid—was left in charge of one half of the army, which raided the Armeniac Theme and took the small fort of Semaluos.

[40][41][42] In June 781, as the Arab invasion force assembled at Hadath under Abd al-Kabir, a great-great-nephew of the Caliph Umar (r. 634–644), and again prepared to launch their annual raid, Empress Irene called up the thematic armies of Asia Minor and placed them under the eunuch sakellarios John.

The ensuing battle resulted in a costly Arab defeat, forcing Abd al-Kabir to abandon his campaign and retreat to Syria.

[51][52] On 9 February 782, His son, Harun departed Baghdad; the Arabs crossed the Taurus Mountains by the Cilician Gates, and swiftly took the border fortress of Magida.

The accounts of subsequent events in the primary sources (Theophanes the Confessor, Michael the Syrian, and al-Tabari) differ on the details, but the general course of the campaign can be reconstructed.

[41][53][54] According to Warren Treadgold, the Byzantine effort seems to have been led by Irene's chief minister, the eunuch Staurakios, whose strategy was to avoid an immediate confrontation with Harun's huge army, but wait until it had split up and advanced to meet its various detachments independently.

[55] The Thracesians under Lachanodrakon confronted al-Barmaki at a place called Darenos, but were defeated and suffered heavy losses (15,000 men according to Theophanes, 10,000 according to Michael the Syrian).

The outcome of al-Rabi's siege of Nakoleia is unclear, but he was probably defeated; Theophanes's phrasing may imply that the town was taken, but Michael the Syrian reports that the Arabs suffered great losses and failed to capture it, a version of events confirmed by hagiographic sources.

In the ensuing battle, Niketas was wounded and unhorsed in single combat with the Arab general and forced to retire, probably to Nicomedia, where the imperial tagmata (professional guard regiments) under the Domestic of the Schools Anthony were assembled.

Lacking ships to cross the Bosporus, and with no intention of assaulting Constantinople in the first place, Harun probably intended this advance only as a show of force.

Consequently, after plundering the Byzantine capital's Asian suburbs, Harun turned his army back, but during his march along the valley of the Sangarius River, east of Nicaea, he was surrounded by the forces of the tagmata under Anthony in his rear and of the Bucellarians under their general Tatzates to his front.

[58][61][62] Fortunately for him, at this point Tatzates, an Armenian prince who had defected from his Arab-ruled homeland to the Byzantines in 760 and was closely associated with the iconoclast regime of Constantine V, secretly made contact with him.

As the German Byzantinist Ralph-Johannes Lilie writes, "Tatzates did not see any big opportunities for himself under the new regime and indeed used the good chance that the situation offered him".

[57][61][62][63] Thus, when Harun asked for negotiations, Irene dispatched a delegation of three of her most senior officials: the Domestic Anthony, the magistros Peter, and Staurakios himself.

Confident of their military position, they neglected to secure promises for their safety or hostages of their own, so that when they arrived in the Arab camp, they were made prisoners.

Coupled with the treachery of Tatzates and the unreliability of the troops under his command, Irene was now forced to negotiate for their release, especially of her trusted aide Staurakios.

[57][61][62][63] The two states concluded a three-year truce in exchange for a heavy annual tribute—the Arab sources mention various amounts between 70,000 and 100,000 gold nomismata, while one also adds 10,000 pieces of silk.

[63] Tabari's account records that the tribute amounted to "ninety or seventy thousand dinars", to be paid "at the beginning of April and in June every year".

[64][65] In addition, the Byzantines were obliged to provide provisions and guides for Harun's army on its march home, and to hand over Tatzates's wife and property.

Al-Mahdi focused on the persecution of the zanadiqa in order to improve his standing among the purist Shi'i, who wanted a harder line on heresies, and found the spread of syncretic Muslim-polytheist sects to be particularly virulent.

Finally, al-Khayzuran held her own court in the harem and in her quarters where she met petitioners, both men and women, who asked her for favors or to intercede on their behalf with her husband, the caliph.

Former caliphs who embarked on the hajj pilgrimage to Mecca had made the long voyage with canteens full of muddy water and satchels of dates.

Mahdi saw no reason for such extreme self-restraints, instead, he traveled like royalty, and even brought ice lugged all the way from the mountains of northern Persia so that his drinks could be cold.