On 11 April 1963, John expanded further on this in Pacem in terris (), the first encyclical addressed to both Catholics and non-Catholics. In it, the pope linked the establishment of world peace to the laying of a foundation consisting of proper rights and responsibilities between individuals, social groups, and states from the local to the international level. He exhorted Catholics to understand and apply the social teachings: This document, issued at the height of the Cold War, also included a denunciation of the nuclear arms race and a call for strengthening the United Nations. Second Vatican Council The primary document from the Second Vatican Council concerning social teachings is Gaudium et spes, the "Pastoral Constitution on the Church and the Modern World", which is considered one of the chief accomplishments of the council. Unlike earlier documents, this is an expression of all the bishops, and covers a wide range of issues of the relationship of social concerns and Christian action. At its core, the document asserts the fundamental dignity of each human being, and declares the church's solidarity with both those who suffer, and those who would comfort the suffering: Other conciliar documents such as Dignitatis humanae, drafted largely by John Courtney Murray, an American Jesuit, have important applications to the social teachings of the church on freedom today. Pope Paul VI Like his predecessor, Pope Paul VI gave attention to the disparities in wealth and development between the industrialized West and the Third World in his 1967 encyclical Populorum progressio (The Development of Peoples). It asserts that free international trade alone is not adequate to correct these disparities and supports the role of international organizations in addressing this need. Paul called on rich nations to meet their moral obligation to poor nations, pointing out the relationship between development and peace. The intention of the church is not to take sides, but to be an advocate for basic human dignity: The May 1971 apostolic letter Octogesima adveniens addressed the challenge of urbanization and urban poverty and stressed the personal responsibility of Christians to respond to injustice. For the tenth anniversary of the Second Vatican Council (26 October 1975), Paul issued Evangelii nuntiandi (Evangelization in the Modern World). In it he asserts that combating injustice is an essential part of evangelizing modern peoples. Pope John Paul II Pope John Paul II continued his predecessors' work of developing the body of