For nearly two thousand years, popes have communicated to the world primarily through their letters. In the premodern world, the papal chancery turned out tens of thousands of letters a year. On occasion, a letter dealt with broad concerns and was intended to circulate through the churches of a given region. Such letters became known as encyclicals. In the modern period, papal encyclicals have become the primary medium through which the papacy exercises its teaching office. Through them, the popes address theological topics of especially timely concern, applying Christian doctrine to the immediate circumstances of the day.
This encyclical is a testament to its time. Written during the turbulent 1950s and 1960s, it demonstrates Blessed Pope John XXIII’s commitment to bringing the Gospel to humankind.