The Book of Psalms is a book in the Hebrew and Christian bibles that contains a collection of song lyrics with religious themes. Scholars believe a variety of authors wrote the psalms over a large span of time, with many individual psalms attributed to King David.
Scholars debate whether King David actually wrote the psalms attributed to him, but they do agree that many of the hymns date back to the time of his reign or before (circa 1000 B.C.). Other psalms date to the period after the Babylonian exile, which ended in 538 B.C.
Different religious traditions number the psalms differently, though most Jewish, Protestant and Catholic versions of the book each include 150 individual works. The Eastern Orthodox Church's Septuagint Bible includes a 151st psalm, while some versions of the Bible used by Middle Eastern Syriac churches have 155 psalms.