The New Testament is the second major part of the Christian biblical canon, the first part being the Old Testament, based on the Hebrew Bible. The Greek New Testament discusses the teachings and person of Jesus, as well as events in first-century Christianity. Christians regard both the Old and New Testaments together as sacred scripture. The New Testament (in whole or in part) has frequently accompanied the spread of Christianity around the world. It reflects and serves as a source for Christian theology and morality. Both extended readings and phrases directly from the New Testament are also incorporated (along with readings from the Old Testament) into the various Christian liturgies. The New Testament has influenced religious, philosophical, and political movements in Christendom, and left an indelible mark on literature, art, and music. The New Testament is an anthology, a collection of Christian works written in the common Greek language of the first century, at different times by various writers, who were early Jewish disciples of Jesus. In almost all Christian traditions today, the New Testament consists of 27 books. The original texts were written in the first and perhaps the second centuries of the Christian Era, generally believed to be in Koine Greek, which was the common language of the Eastern Mediterranean from the Conquests of Alexander the Great (335-323 BC) until the evolution of Byzantine Greeks (c. 600). All the works that eventually became incorporated into the New Testament seem to have been written no later than around 150 AD, and some scholars would date them all to no later than 70 AD or 80 AD.