The tune ‘Old 100th’, is a melody from Pseaumes Octante Trois de David (1551), and is one of the best known melodies in all Christian musical traditions. The melody receives its name from the hymn All Creatures that on Earth do Dwell by William Kethe, a paraphrasing of the 100th psalm of David, which is the most familiar hymn sung to this music. The tune is usually attributed to the French composer Loys Bourgeois (c.1510 – c.1560).
The hymn Praise to God by Isaac Watts is a paraphrasing of Psalm 117, with a third verse by Thomas Ken, and is also sung to the tune of the Old 100th. These hymns are significant because the last verse of each is a doxology, a statement of praise to God, usually in the form of the Holy Trinity, a fundamental belief for most Christians. The doxologies based on the Old 100th are sung in Christian churches around the world.