During his personal reign James VI attempted to revive the song schools, with an act of parliament passed in 1579, demanding that councils of the largest burghs set up "ane sang scuill with ane maister sufficient and able for insturctioun of the yowth in the said science of musik". Five new schools were opened within four years of the act coming into force, and by 1633 there were at least twenty-five. Most of those burghs without song schools made provision within their grammar schools. Polyphony was incorporated into editions of the Psalter from 1625, but in the few locations where these settings were used, the congregation sang the melody and trained singers the contra-tenor, treble and bass parts. However, the triumph of the Presbyterians in the National Covenant of 1638 led to an end of polyphony, and a new psalter in common metre, without tunes, was published in 1650. In 1666 "The Twelve Tunes for the Church of Scotland, composed in Four Parts" (which actually contained 14 tunes), designed for use with the 1650 Psalter, was first published in Aberdeen. It would go through five editions by 1720. By the late seventeenth century these two works had become the basic corpus of the psalmody sung in the Kirk.