Hıristiyan asıllı dedelerinden birine nispetle daha çok İbnü’l-Mûsalâyâ olarak tanınan Ebû Sa‘d Alâ b. Hasan b. Vehb 412 (1066) yılında Bağdat’ın Kerh bölgesinde doğmuştur. Babası Hasan b. Vehb Abbâsî Halifesi Kāim-Biemrillâh (422-467 / 1031-1075) döneminde Dîvânü’l-inşâ’da kâtip olarak çalışmıştır. Babasının vefatından kısa bir süre sonra (432/1040) aynı divanda kâtiplik yapmaya başlayan İbnü’l-Mûsalâyâ kısa bir süre sonra Dîvânü’l-inşâ reisliğine atanmıştır. Bu görevini devam ettirirken Muktedî-Biemrillâh (467-487 / 1075-1094) ve Müstazhir-Billâh (487-512 / 1094-1118) dönemlerinde üç defa nâibülvezir olarak görevlendirilmiş ve 497 (1104) yılında Bağdat’ta vefat etmiştir. Abbâsî bürokrasisinin çeşitli kademelerinde elli yılı aşkın bir süre görev yapan İbnü’l-Mûsalâyâ’nın kaleme aldığı resmî ve şahsî mektuplardan altmış altı tanesi zamanımıza kadar ulaşmıştır. Bu mektupların büyük bir kısmı (yaklaşık kırk tanesi) Tuğrul Bey, Alparslan, Melikşah, Amîdülmülk el-Kündürî ve Nizâmülmülk gibi Büyük Selçuklu sultanları ve vezirlerine hitaben yazıldığı için Abbâsî-Selçuklu ilişkileri açısından birinci elden kaynak özelliği taşımaktadır. Diğer taraftan Fahrüddevle ve İbn Dârest’in vezirliğe, bir kişinin de kādılkudatlığa tayin edildiğine dair halife tarafından çıkarılan tevkī‘ metinlerini ihtiva etmesi ve bazı divanlarla ilgili önemli ipuçları sunması bu mektupların geç dönem Abbâsî idarî tarihî açısından da kıymetli birer kaynak olduğunu göstermektedir. Bu çalışmada önce İbnü’l-Mûsalâyâ’nın hayatı üzerinde durulacak, ardından söz konusu mektuplardan hareketle Büveyhîler’den Selçuklular’a geçiş sürecinde Abbâsî idarî tarihine dair bazı bilgiler verilecektir.

Abu Saʿd ʿAlā’ b. Ḥasan, also known in sources as Ibn al-Mūṣalāyā out of respect for his Christian grandfather, was born on 6 Shawwāl 412 (13 January 1022) in Karkh quarter of Baghdad. Ibn al-Mūṣalāyā’s father Ḥasan b. Wahb was the first family member employed in the Abbasid administration, serving as a scribe in the chancery department during the caliphate of al-Qā’im (r. 1031-1075). Like his father, Ibn al-Mūṣalāyā chose a scribal career for himself and began working for the chancery department in his twenties. He was appointed head of the chancery sometime before 443/1051 and he remained in this position for more than fifty years. One of the turning points in his life was his conversion to Islam during the reign of al-Muqtadī, after having served as head of the chancery more than forty years. In addition to his role in the chancery, he also served as vice-vizier three times during a period of transitional rule from the Buyids to the Seljuks. He acquired considerable esteem among the Abbasid caliphs and Seljuk sultans for his ethical virtues and success in his job. Ibn al-Mūṣalāyā lost his sight at an old age. Likely due to the fact that he never married, no information about his family members exists in the sources.   From the letters of Ibn al-Mūṣalāyā, only the second part and most probably only a small section is extant. These letters were collected by an anonymous scribe on 8 Jumādā al-ākhir 603 (10 January 1207), with the only surviving copy being kept in the Tunisian National Library. ‘Iṣām ‘Aqla prepared a critical edition of this letter, titled, al-Khilāfa al-‘Abbāsiyya fī daw’i rasāʾil Amīn al-dawla: Dirāsa wa al-taḥqīq in 1997 as his Ph.D. dissertation in Jordan University; it was published with the title Rasāʾil Amīn al-dawla Ibn al-Mūṣalāyā in 2003. The purpose of this article is to draw researchers’ attention to the letters of Ibn al-Mūṣalāyā, which constitute rare examples of research into Abbasid administrative history. The article consists of two parts. The first part outlines the life of Ibn al-Mūṣalāyā. The second part, based on the contents of the letters, examines certain Abbasid institutions such as the vizierate, the chief-judgeship and certain bureaus during the fifth/eleventh century. The letters, made up of sixty six texts, were written from 451 (1059) to 491 (1097). Ibn al-Mūṣalāyā addressed three of them personally to the Seljuk viziers ‘Amīd al-Mulk al-Kundurī and Niẓām al-Mulk, and a prominent Christian physician Mu‘tamid al-dawla Abū al-Faraj Yaḥyā b. Saʿīd b. Tilmīdh (d. 512/1118). Further, he addressed seven of them to Abbasid Caliph al-Muqtadī (d. 487/1094), one to al-Mustaẓhir (d. 512/1118), and forty-seven to al-Qā’im (d. 467/1075). We could not verify the addressee(s) of the remaining eight letters. Most of the letters (27 of them) penned on behalf of the Abbasid caliphs were addressed to Seljuk sultans such as Tughrul Beg, Alp Arslan, Malikshah, etc. Two letters of Ibn al-Mūṣalāyā are particularly salient, as they include chancery texts about two individuals, Ibn Dārast and Fakhr al-dawla Muḥammad b. Jahīr, who were ultimately appointed to the post of vizierate. Although sources mention that appointments to vizierate were usually accompanied by chancery documents issued under the caliph’s name, they provide no detail for the format or the content of these documents. The first of these letters begins with panegyric phrases for the caliph whereas the second does so by thanking God and relaying greetings to the Prophet. Both then talk about the necessary qualifications of the candidate viziers and then end with sections that include caliphal advice to the viziers. In addition, both letters talk about political conditions at the time of the each vizierial appointment, respectively. Furthermore, for the same occasion of these appointments, three other letters addressed to the Seljuk sultan and vizier also address similar political realities. Therefore, these chancery documents, penned in two different genres, shed light on the Abbasid vizierate at a time when the Seljukid influence was dominant. They also address political developments, providing historians with political insight and context. The letter on the chief-judgeship outlines the necessary qualifications of a chief-judge, his authority and responsibilities, and the people working under his supervision. It then details the adjudication process while a chief-judge is deciding on a matter by consulting the Quran, Prophetic tradition, communal consensus and his own personal view. It is worth noting here that the letter does not specifically advise adopting a particular school’s position, should a chief-judge consult to his own view. That could mean that judges from different schools were eligible for the appointment as chief-judge, and that a chief-judge should not limit himself to his school’s adopted positions on specific matters. Bureaus (dīwāns) were of another type of institution about which we find limited information. Although Ibn al-Mūṣalāyā worked long in the Chancery Bureau (Dīwān al-inshā’), he offered very little content directly related to this bureau. However, although he lived most of his life as Christian, his attention to Quranic verses and prophetic traditional texts shows that non-Muslim scribes were well educated in these areas, like their Muslim colleagues. In addition, these letters mention the existence of bureaus such as Dīwān al-tarikāt al-ḥashriyya and Dīwān al-jawālī, revealing the importance of these institutional structures to the Abbasid administration.