Kingdom songs are the hymns sung by Jehovah's Witnesses at their religious meetings. Since 1879, the Watch Tower Society has published hymnal lyrics; by the 1920s they had published hundreds of adapted and original songs, and by the 1930s they referred to these as "Kingdom songs" in reference to God's Kingdom. With the 1966 release of Singing and Accompanying Yourselves with Music in Your Hearts, a policy was introduced to use only songs written by Witnesses. Subsequent collections were released in 1984 and in 2009, each retaining, retiring, or revising previous songs and introducing new songs. By 2019, the hymnal "Sing Out Joyfully" to Jehovah was available in over 200 languages, including several sign languages. In addition to songbooks containing sheet music and lyrics, releases in various audio formats have included vocals in several languages, piano instrumentals, and orchestral arrangements. Use in worship Typically, Jehovah's Witnesses sing three songs at their meetings for worship. The entire congregation sings, accompanied by an orchestral recording. Meetings open and close with a song and prayer, along with a song during an interlude between the two or three sections of the meeting. Songs are selected to match the theme of the meeting program. The song used to introduce the public talk is normally chosen by the speaker. Songs are used at assemblies and conventions, and sometimes at different events at Watch Tower Society branch offices. Jehovah's Witnesses' publications suggest that Witnesses listen to this music in their personal time. Collections In the late 19th century, the Bible Students (from which Jehovah's Witnesses arose) used many well-known songs and melodies. They also used well-known melodies with their own lyrics. The prefaces of Songs of the Bride and Poems and Hymns of Dawn indicate that these hymnals include hymns adapted from other Protestant hymnals such as Hymns of the Morning, Gospel Hymns, Jubilee Harp, Winnowed Hymns, Epworth Hymnal and Songs of Pilgrimage. These melodies were often works of famous composers, including Ludwig van Beethoven and Joseph Haydn. Lyrics were often adapted from works of famous hymnal writers including Philip P. Bliss, Horatius Bonar, Fanny Crosby, Philip Doddridge, Thomas Hastings, John Newton, Isaac Watts and Charles Wesley. In 1877, Charles Taze Russell and Nelson H. Barbour announced Songs of the Morning in their book Three Worlds. Songs of the Bride, a collection of 144 songs, was published in 1879. In 1890, Poems and Hymns of the Millennial