The mid-to-late 19th century witnessed an increase in popularity of political Catholicism across Europe. According to historian Michael A. Riff, a common feature of these movements was opposition not only to secularism, but also to both capitalism and socialism. In 1891 Pope Leo XIII promulgated "Rerum novarum", in which he addressed the "misery and wretchedness pressing so unjustly on the majority of the working class" and spoke of how "a small number of very rich men" had been able to "lay upon the teeming masses of the laboring poor a yoke little better than that of slavery itself". Affirmed in the encyclical was the right of all men to own property, the necessity of a system that allowed "as many as possible of the people to become owners", the duty of employers to provide safe working conditions and sufficient wages, and the right of workers to unionise. Common and government property ownership was expressly dismissed as a means of helping the poor.