So, Max, every Pope prior to Leo didn't want Christians to be protected from the Devil?
This is a good example of the antiquarianism that was condemned by Pope Pius XII. Catholics should never strive to return to some earlier period of mythical purity, but should be grateful for all of the assistance towards salvation that has been developed by the Church over its many centuries of existence. Popes didn't need to warn against communism a thousand years ago, but today they do. Pope Leo XIII saw a vision of Satan oppressing the Church, and he instituted the prayers to protect against this. Those prayers were abandoned at the time of Vatican II. Lucky thing there's been no demonic oppression of the Church since then, and instead we've experienced a "new springtime of the faith," isn't it?