Sacred art is imagery intended to uplift the mind to the spiritual. It can be an object to be venerated not for what it is but for what it represents, though venerated objects are more properly called sacramentals. Idols, which are worshipped in and of themselves, are not considered sacred art.
Christian European sacred art
Sacred art was common in the European Middle Ages, but many of the greatest masters commissioned by the Roman Catholic Church lived during the Renaissance. It was during this time that Michelangelo Buonarotti painted the Sistine Chapel and carved the Pietá, Gianlorenzo Bernini created the massive columns in St. Peter's Basilica, and Leonardo da Vinci painted the Last Supper.
Most Christian sacred art is allusive, or built around themes familiar to the intended observer. One of the most common Christian themes is that of a woman (the Virgin Mary) holding a child (the infant Jesus). Another is that of Jesus on the cross.
The genre of sacred art has lost much of its vigor since the Renaissance, but the themes are still popular, a 20th century example being Salvador Dalí's The Crucifixion.
Tibetan Buddhist sacred art
Tibetan art includes thangkas and mandalas, sometimes including depictions of Buddhas and bodhisattvas. Creation of Buddhist art is usually done as a meditation, an example of which is the creation of a sand mandala by monks. The work is rarely, if ever, signed by the artist. Other Tibetan Buddhist art includes metal ritual objects, such as the vajra and the phurba.
Muslim sacred art
Because of the strict injunctions against such depictions of humans or animals which might result in idol-worship, Islamic art developed a unique character, utilizing a number of primary forms: geometric, arabesque, floral, and calligraphic, which are often interwoven. From early times, Muslim art has reflected this balanced, harmonious world-view. It focuses on spiritual essence rather than physical form. It offers no pictures of saints or illustrations of stories from the Quran, but rather expresses fundamental concepts such as the infinite nature of God through repetitive geometric designs without beginning or end.