Iconoclasm was the movement to contest the use and veneration of religious images and icons that arose in the early days of Christianity.
Iconoclasm, as a political-religious ideology, intensified from the 8th century onwards in the Byzantine Empire. The culmination of this movement was the publication of a law by King Leo III that ordered the destruction of all religious images, prohibiting their veneration.
It is worth remembering that at that time religious images were widely used as tools for converting pagans into Christians.
The Byzantines, however, believed that the use of images for conversion caused people not to practice the religious reflection that was necessary for the true experience of Christianity, but they only converted by finding the icons "beautiful".
Iconoclasm still believed that the attention given to sacred images would result in idolatry of these, this act is considered a sin in Christianity.
Thus, several iconoclasts (followers of this movement) destroyed numerous images that represented biblical characters and scenes. With this, the iconoclasts sought to institute a “purification of Christianity”, reducing the influence that images had on people's faith.
Etymologically, iconoclasm literally means "image breaker", a term originated from the union of Greek words eikon, which means “image” or “icon”; and Klastein, which means “break”.
See also: the meaning of Iconoclast.
The opposite of iconoclasm is the iconophilia or iconoduly (“worshiper of images”, literally translated from Greek), ideas that advocate the use of religious images as part of Christian worship.
The iconoclastic movement persisted until the mid-ninth century, when the Second Council of Nicaea approved the dogma of icon worship as a representation of the Christian faith.
See also: the meaning of Iconography.