Antireligion is opposition to religion. The term may be used to describe opposition to organized religion, or to describe a broader opposition to any form of belief in the supernatural or the divine. Antireligion is distinct from atheism (the absence of a belief in deities) and antitheism (an opposition to belief in deities), although antireligionists may also be atheists or antitheists.
According to historian Michael Burleigh, antireligion found its first mass expression in revolutionary France in response to organised resistance to "organised ... irreligion...an 'anti-clerical' and self-styled 'non-religious' state."
The Soviet Union directed antireligious campaigns at all faiths, including Christian, Islamic, Buddhist, Jewish, and Shamanist religions. In the 1930s, during the Stalinist period, the government destroyed church buildings or put them into secular use (as museums of religion and atheism, clubs or storage facilities), executed clergy, prohibited the publication of most religious material and persecuted some members of religious groups. Less violent attempts to reduce or eliminate the influence of religion in society were also carried out at other times in Soviet history. For instance, it was usually necessary to be an atheist in order to acquire any important political position or any prestigious scientific job; thus many people became atheists in order to advance their careers. Different sources disagree on the results of all this, with some claiming the death of 21 million Russian Orthodox Christians by the Soviet government, not including other religious groups or persecutions without killings, and other sources stating that only up to 500,000 Russian Orthodox Christians were persecuted by the Soviet government, not including other religious groups.