Prayers recorded in the Bible are personal compositions rather than a standard text. According to tradition, many of the current standard prayers were composed by the sages of the Great Assembly in the early Second Temple period (516 BCE – 70 CE). The language of the prayers, while clearly from this period, often employs Biblical idiom. The main structure of the modern prayer service was fixed in the tannaic era (1st-2nd centuries CE), with some additions and the exact text of blessings coming later. Jewish prayerbooks emerged during the early Middle Ages during the period of the Geonim of Babylonia (6th–11th centuries CE).