|Preach to the choir|
|Crux of the matter|
|Speak of the devil|
|An act of faith|
Iconoclasm is the destruction of icons that are part of a certain set, such as religious symbols. A person who performs this is an iconoclast.
The original meaning refers to those who destroyed religious iconography which they believed to be idolatrous. There were some examples of this in medieval Byzantine Christianity and Islam, but some of the most notable bouts of iconoclasm took place during the Protestant Reformation of the 16th and 17th centuries, when Puritans removed or destroyed religious statues, paintings, stained glass windows and other ornamentation which they believed to be a violation of the Second Commandment. Some iconoclasm was done peacefully by reforming ministers and congregations, but much of it was committed by rioting crowds or soldiers. This was particularly the case during the English Civil Wars and the Commonwealth era (1642 to 1660).
Some sects of Islam continue to be aniconist, particularly some Salafis and Wahhabis. In 1965, one of King Faisal's nephews was killed while leading an assault on Saudi Arabia's first television station.
In modern usage, the term "iconoclasm" is rarely used for physical destruction or vandalism. Instead an iconoclast is anybody who challenges, rejects or redefines a popular image or perception, particularly one held to be "sacred" in some way, although this is often in a secular rather than religious sense. Sometimes this can be a visual defacement of a picture, such as the Sex Pistols' modified portraits of Queen Elizabeth II on their record sleeve artwork. More often iconoclastic behaviour takes the form of criticising accepted heroes or concepts. However, this also means that 'iconoclast' is a popular self-description among cranks and their fans accompanied by claims that, for instance, the scientific consensus they don't like amounts to a religious dogma.