It has been a month of anniversaries. Exactly 400 years ago Galileo first got into hot water with the Church over the Copernican system. Starting with a hearing of the Holy Office on 23 February, the affair stretched across all of spring 1616 including Galileo’s meeting with Cardinal Bellarmine on 26 February, and the formal censure of Copernicus’ work issued on 5 March. Curiously, Galileo’s works were not mentioned at that time.

By the end of the nineteenth century, of course, the Church view on astronomy had changed. Pope Leo XIII in his encyclical Aeterni Patris (1879) essentially endorsed Galileo’s view on science and religion. And on 14 March 1891, 125 years ago, Pope Leo promulgated a “Motu Proprio” that established the modern Vatican Observatory. Two months later, his encyclical Rerum Novarum would mark a new beginning of the Church’s engagement with the modern world.

Finally, just 30 years ago this month, on 15 March 1986, the Vatican Secretariat of State informed the Vatican Observatory that Pope John Paul II had given his blessing to build the Vatican Advanced Technology Telescope. Since then, that telescope on a remote Arizona mountaintop has been our mainstay for astronomical observations.