On May 15, 1893, Pope Leo XIII issued his encyclical Rerum Novarum, ushering in modern Catholic Social Teaching. In Rerum Novarum, the Holy Father reflected on the industrial revolution and the wholesale transformation it brought, with peasant farmers and artisans who previously owned their land and shops converted wholesale into employees working for wages. He concluded that workers had a right to organize in trade unions to improve their condition and hoped more would organize — 42 years before the US Congress recognized this and passed the National Labor Relations Act in 1935. He also said that every worker has the right to a living wage and if necessary the government would have to regulate the labor market to ensure this happened — 45 years before the US Congress recognized this and passed the Fair Labor Standards Act, establishing the federal minimum wage.
In his encyclical Caritas in Veritate, Pope Benedict XVI observed that in an era of globalization,
The repeated calls issued within the Church’s social doctrine, beginning with Rerum Novarum, for the promotion of workers’ associations that can defend their rights, must be honoured today even more than in the past .