Many of these letters contain questions about church reform and liturgical or doctrinal matters. Some have joined the Episcopal Church, which still retains much of the Catholic liturgical form. In making his changes he overthrew 1400 years of eucharistic liturgical doctrine and practice. Ascension is one of the Twelve Great Feasts of the Orthodox liturgical year. Certain religions also have a sacred language often used in liturgical services. The psalm is sung to a wide variety of tunes both liturgical and secular. The most prominent form of sacred and liturgical jazz is the jazz mass. There was an increase of literature, the arts, architecture, jurisprudence, liturgical and scriptural studies. Countless hymns survive from this time period (both liturgical and paraliturgical). It is used to chant all forms of liturgical worship. Some are used by all Western Christians in liturgical traditions. The Church's year combines two cycles of liturgical celebrations. A canonical sundial is one that indicates the canonical hours of liturgical acts. It embraces liturgical, holiness, and evangelical elements. Unfortunately, relatively little has been written about sacred and liturgical jazz.