When Catholics in the Western world think of ecumenism and full Church unity, our natural tendency is to think first of healing the breach of the 16th century Reformation.

The Second Vatican Council's Decree on Ecumenism (Unitatis Redintegratio) staked the cause of Christian unity clearly on the ground of Church renewal.

Perhaps the most important traditional Catholic teaching that received new life at the Second Vatican Council was that of the hierarchy of truths. The Decree on Ecumenism, no. 11, presented the notion that some truths are more central than others.

The Second Vatican Council’s Decree on Ecumenism had several important things to say to the Catholic community. However, the most important things about the decree were that it was written, it was overwhelmingly approved and it called for dialogue among separated Christians.

For the French Dominican theologian Yves Congar, the presentation of a schema on ecumenism on the floor of the Second Vatican Council must have seemed like a dream, one too good to be true.

On Nov. 18, 1963, Vatican II's proposed document on ecumenism reached the floor of the council. One of the main reasons Pope John XXIII had called the Second Vatican Council was to further the quest for Church unity and so this was an historic day.

In the first two sessions of the Second Vatican Council, only two documents received final approval. One – the Constitution on the Sacred Liturgy – had an enormous effect on the life of the Church. The other – the Decree on Social Communications (Inter Mirifica) – has been virtually ignored.

One of the more significant points of evolution in Church teaching that emerged from the Second Vatican Council was that on the Blessed Virgin Mary. It was an evolution, however, that came with considerable gnashing of teeth and a most emotional debate.

The authority of the college of bishops was not only one of the most important issues discussed at the Second Vatican Council, it was also among the most controversial.

In looking back on the Second Vatican Council, it appears so natural that the council met for about two months every fall from 1962 through 1965.