Talmudic and midrashic sources contain hymns of the creation usually based on homiletic expansions of metaphorical descriptions and personifications of the created world in the Bible. The explicitly homiletic background of some of the hymns in Perek Shira indicates a possible connection between the other hymns and Tannaitic and Amoraic homiletics, and suggests a hymnal index to well-known, but mostly unpreserved, homiletics. The origin of this work, the period of its composition and its significance may be deduced from literary parallels. A Tannaitic source in the tractate Hagiga of the Jerusalem (Hag. 2:1,77a—b) and Babylonian Talmud (Hag. 14b), in hymns of nature associated with apocalyptic visions and with the teaching of ma’aseh merkaba serves as a key to Perek Shira’s close spiritual relationship with this literature. Parallels to it can be found in apocalyptic literature, in mystic layers in Talmudic literature, in Jewish mystical prayers surviving in fourth-century Greek Christian composition, in Heikhalot literature, and in Merkaba mysticism. The affinity of Perek Shira with Heikhalot literature, which abounds in hymns, can be noted in the explicitly mystic introduction to the seven crowings of the cock — the only non-hymnal text in the collection — and the striking resemblance between the language of the additions and that of Shi’ur Koma and other examples of this literature. In Seder Rabba de-Bereshit, a Heikhalot tract, in conjunction with the description of ma’aseh bereshit, there is a clear parallel to Perek Shira’s praise of creation and to the structure of its hymns. The concept reflected in this source is based on a belief in the existence of angelic archetypes of created beings who mediate between God and His creation, and express their role through singing hymns. As the first interpretations of Perek Shira also bear witness to its mystic character and angelologic significance, it would appear to be a mystical chapter of Heikhalot literature, dating from late Tannaitic — early Amoraic period, or early Middle Ages.