al-Mansur Caliph of the Abbasid Caliphate from AD 754 to AD 775.
Al-Mansur or Abu Ja'far Abdallah ibn Muhammad al-Mansur ( Arabic: أبو جعفر عبدالله بن محمد المنصور‎‎) was the second Abbasid Caliph reigning from 754 AD to 775 AD.

Al-Mansur is generally regarded as the real founder of the Abbasid Caliphate, and during his reign, a committee, mostly made up of Syriac-speaking Christians, was set up in Baghdad with the purpose of translating extant Greek works into Arabic.

He is also known for founding the 'round city' of Madinat al-Salam which was to become the core of imperial Baghdad.
al-Mansur
Epithet: al-Mansur ("the Victorious")
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An AR Dirham struck 772 AD in Madinat-al-Salam
Obverse: Margin: بسم الله ضرب هذا الدرهم بمدينة السلام سنة خمس و خمسين و مئة Central: لا اله الا الله وحده لا شرك له ¨

Reverse: Margin: محمد رسول الله ارسله بالهدى و دين الحق ليظهره على الدين كله ولو كره المشركون Center: محمد رسول الله بخ بخ

Diameter: 25.4 mm
Die Orientation: 6 H
Weight: 2.83 g
Translation of obverse:

Margin: "In The Name of God. This dirham was struck in Madinat al-Salam in the year five and fifty and one hundred (155)"

Center: There is no diety except |
(the one) God alone |
He has no equal

Translation of reverse:

Margin: Muhammad is the messenger of God. He sent him with guidance and the true religion to reveal it to all religions even if the polytheists abhor it.

Center: Muhammad
The Messanger
Of God
(Bakh Bakh)
Album 213.1.
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An AR Dirham struck 765-766 AD in Madinat-al-Salam
Obverse: Margin: بسم الله ضرب هذا الدرهم بمدينة السلام سنة ثمان و أربعين و مئة Center: لا اله الا الله وحده لا شريك له

Reverse: Margin: محمد رسول الله ارسله بالهدى و دين الحق ليظهره على الدين كله ولو كره المشركون Center: محمد رسول الله بخ

Diameter: 25 mm
Die Orientation: 3 H
Weight: 2.85 g

Year 148 AH=765-766 AD

Translations:

Obverse margin: "In The Name of God. This dirham was struck in Madinat-al-Salam in the year eight and forty and one hundred"

Obverse center: "There is no deity except (the one) God, he has no equal"

Reverse margin: "Muhammad is the messenger of God. He sent him with guidance and the true religion to reveal it to all religions even if the polytheists abhor it."

Reverse center: "Muhammad The Messenger Of God (Bakh)"

Album 213.1; Lavoix 660