The New Testament (Greek: Καινὴ Διαθήκη, Kainē Diathēkē) is the name given to the secon half of the Christian Bible, the first half being the Hebrew Bible (also called by Jews Tanakh), known to Christians as the Old Testament. It is sometimes called the Greek Testament or Greek Scriptures, or the New Covenant – which is the literal translation of the original Greek. The original texts were written in Koine Greek by various authors after c. AD 45 and before c. AD 140. Its 27 books were gradually collected into a single volume over a period of several centuries. The New Testament is a central element of Christianity, and has played a major role in shaping modern Western culture. Although certain Christian sects differ as to which works are included in the New Testament, the vast majority of denominations have settled on the same twenty-seven book canon: it consists of the four narratives of Jesus Christ's ministry, called "Gospels"; a narrative of the Apostles' ministries in the early church, which is also a sequel to the third Gospel; twenty-one early letters, commonly called "epistles" in Biblical context, written by various authors and consisting mostly of Christian counsel and instruction; and an Apocalyptic prophecy, which is technically the twenty-second epistle. Although the traditional timeline of composition may have been taken into account by the shapers of the current New Testament format, it is not, nor was it meant to be, in strictly chronological order. Though Jesus speaks Aramaic in it, the New Testament (including the Gospels) was written in Greek because that was the lingua franca of the Roman Empire.