1. The Centenary of the promulgation of the Encyclical which begins with the words "Rerum novarum",1 by my predecessor of venerable memory Pope Leo XIII, is an occasion of great importance for the present history of the Church and for my own Pontificate. It is an Encyclical that has the distinction of having been commemorated by solemn Papal documents from its fortieth anniversary to its ninetieth. It may be said that its path through history has been marked by other documents which paid tribute to it and applied it to the circumstances of the day.²

In doing likewise for the hundredth anniversary, in response to requests from many Bishops, Church institutions, and study centres, as well as business leaders and workers, both individually and as members of associations, I wish first and foremost to satisfy the debt of gratitude which the whole Church owes to this great Pope and his "immortal document".³ I also mean to show that the vital energies rising from that root have not been spent with the passing of the years, but rather have increased even more. This is evident from the various initiatives which have preceded, and which are to accompany and follow the celebration, initiatives promoted by Episcopal Conferences, by international agencies, universities and academic institutes, by professional associations and by other institutions and individuals in many parts of the world.

2. The present Encyclical is part of these celebrations, which are meant to thank God — the origin of "every good endowment and every perfect gift" (Jas 1:17) — for having used a document published a century ago by the See of Peter to achieve so much good and to radiate so much light in the Church and in the world. Although the commemoration at hand is meant to honour Rerum novarum, it also honours those Encyclicals and other documents of my Predecessors which have helped to make Pope Leo's Encyclical present and alive in history, thus constituting what would come to be called the Church's "social doctrine", "social teaching" or even "social magisterium".

The validity of this teaching has already been pointed out in two Encyclicals published during my Pontificate: Laborem exercens on human work, and Sollicitudo rei socialis on current problems regarding the development of individuals and peoples.4

3. I now wish to propose a "re-reading" of Pope Leo's Encyclical by issuing an invitation to "look back" at the text itself in order to discover anew the richness of the fundamental principles which it formulated for dealing with the question of the condition of workers. But this is also an invitation to "look around" at the "new things" which surround us and in which we find ourselves caught up, very different from the "new things" which characterized the final decade of the last century. Finally, it is an invitation to "look to the future" at a time when we can already glimpse the third Millennium of the Christian era, so filled with uncertainties but also with promises — uncertainties and promises which appeal to our imagination and creativity, and which reawaken our responsibility, as disciples of the "one teacher" (cf. Mt 23:8), to show the way, to proclaim the truth and to communicate the life which is Christ (cf. Jn 14:6).

A re-reading of this kind will not only confirm the permanent value of such teaching, but will also manifest the true meaning of the Church's Tradition which, being ever living and vital, builds upon the foundation laid by our fathers in the faith, and particularly upon what "the Apostles passed down to the Church"5 in the name of Jesus Christ, who is her irreplaceable foundation (cf. 1 Cor 3:11).

It was out of an awareness of his mission as the Successor of Peter that Pope Leo XIII proposed to speak out, and Peter's Successor today is moved by that same awareness. Like Pope Leo and the Popes before and after him, I take my inspiration from the Gospel image of "the scribe who has been trained for the kingdom of heaven", whom the Lord compares to "a householder who brings out of his treasure what is new and what is old" (Mt 13:52). The treasure is the great outpouring of the Church's Tradition, which contains "what is old" — received and passed on from the very beginning — and which enables us to interpret the "new things" in the midst of which the life of the Church and the world unfolds.

Among the things which become "old" as a result of being incorporated into Tradition, and which offer opportunities and material for enriching both Tradition and the life of faith, there is the fruitful activity of many millions of people, who, spurred on by the social Magisterium, have sought to make that teaching the inspiration for their involvement in the world. Acting either as individuals or joined together in various groups, associations and organizations, these people represent a great movement for the defence of the human person and the safeguarding of human dignity. Amid changing historical circumstances, this movement has contributed to the building up of a more just society or at least to the curbing of injustice.

The present Encyclical seeks to show the fruitfulness of the principles enunciated by Leo XIII, which belong to the Church's doctrinal patrimony and, as such, involve the exercise of her teaching authority. But pastoral solicitude also prompts me to propose an analysis of some events of recent history. It goes without saying that part of the responsibility of Pastors is to give careful consideration to current events in order to discern the new requirements of evangelization. However, such an analysis is not meant to pass definitive judgments since this does not fall per se within the Magisterium's specific domain.