After the foundation the “City of Peace”, whichaccording to al- Yaʿqūbī was built as a palatialcity by the ʿAbbāsid caliph al-Manṣūr in 149/766,Baghdād became a major center for ḥadīth-studies. Many ḥadīth-scholars whopreviously were active in cities like Medina and al-Kūfa moved to Baghdād and continued teaching andlearning ḥadīth there.They also compiled various ḥadīth-collections which in this periodwere primarily musnad-and muṣannaf -works.The musnad-collectionswere named in analogy to the traditions mentionedtherein. These traditions contain an isnād which goes backuninterruptedly to a compan- ion of the ProphetMuḥammad, i.e. they were regarded as “supported(musnad)”. Whereasaḥādīth in musnad-collections arearranged accord- ing to the names of the companions,muṣannaf -worksinclude aḥādīthgrouped according to subjects of Islamiclaw (fiqh). Inaddition to com- piling ḥadīth, these scholars developed majoraspects of the “sciences of ḥadīth” in Baghdād, such as linguistictechniques to understand ḥadīth, techniques oftransmitter-criticism, and criteria for discussingthe authenticity of aḥādīth. Among these scholars were thefamous proto-Sunnīs Yaḥyā b. Maʿīn (d. 233/847), AbūBakr b. Abī Shayba (d. 235/849), and ʿAlī b. ʿUmaral-Dāraquṭnī (d. 385/995) and beside others theproto Shī ʿī scholar Muḥammad b. Ya ʿqūb al-Kulaynī(d. 329/940–1). In addi- tion several ḥadīth-scholars, includingMuḥammad b. Ismāʿīl al-Bukhārī (d. 256/870) and theother authors of the six (Sunnī) canonical ḥadīth- collections, visitedBaghdād during their travels in search of ḥadīth (riḥla fī ṭalab al- ʿilm). However, probably the most famousḥadīth-scholar whowas active in Baghdād was Aḥmad b. Ḥanbal (d.241/855) who compiled an extensive ḥadīth-collection of themusnad-type whichhad a strong impact on later scholarship, inparticular on Ḥanbalite scholars. One of them wasthe famous Baghdādī preacher ʿAbd al-Raḥmān b.al-Jawzī (d. 597/1200) who authored a book on theVirtues of the Imām Aḥmad b.Ḥanbal. In another work of his, i.e. theKitāb quṣṣāṣwa-l-mudhakkirīn, Ibn al-Jawzī quotessome statements presumably uttered by Ibn Ḥan- balin which he reports the latterʼs stance towards thequṣṣāṣ.