March 7 - the "Birthday of Science"
According to the older calendar, March 7 is the feast day of St. Thomas Aquinas, the day he entered into Life.
But today is also the Birthday of Science - science, that is, in the modern sense.
I learned this from a most amazing book, about which you will be hearding more in the not distant future. That book is Science and Creation by Stanley L. Jaki.
So I will quote the relevant parts for you, and then (after Holy Mass) depart for my lab to join the festivities...
Effective reorientation could not come about except through recourse to the deepest resources of faith. This had to imply something dramatic if the guideposts of faith for reason were to be planted with a historic impact.
The dramatic event took place on March 7,1277, when a list of 219 propositions was condemned by Étienne Tempier, bishop of Paris. The wide spectrum of questions over which a firm judgment was passed clearly indicated that the claim about the perennial recurrence of everything in every thirty-six thousand years (Prop. 92), and about the various aspects of the alleged eternity of the world (Prop. 83-91), represented only a most revealing part in a far broader and deeper issue. What ultimately was at stake was man’s rather newly acquired awareness of the contingency of the world with respect to a transcendental Creator, source of all rationality and lawfulness in the macrocosmos as well as in the microcosmos. Even a cursory review of the condemned propositions can show that what philo-sophy needed was not an "autonomy" based on the exclusion of some very real experiences, religious as they could be in character. The true need of philosophy consisted in vistas pointing far beyond the confines of pantheistic monism, however ancient its pedigree could be in the history of man’s speculations about the universe and his destiny in it.
The vindication of the Creator’s attributes opened up far-reaching possibilities for the interpretation of the cosmos. The recognition of the possibility of several worlds (Prop. 27); the rejection of the superlunary material as animated, incorrupt-ible, and eternal (Prop. 31-32); the admission of the possibility of a rectilinear motion for celestial bodies (Prop. 66); the rejection of their actual motion as if sparked by animal desire (Prop. 73); the rejection of the celestial orbs as organs equivalent to the eyes and ears of the human body though not as parts of a celestial machinery (Prop. 75); the rejection of the deterministic influence of stars on individuals from the moment of birth (Prop. 105); the rejection of the necessary production of the "first matter" from the celestial one (Prop. 107); all these de-cisions followed intimately from the effort to safeguard the abilities and exclusive rights of the Creator against any compromise dictated by a narrow rationalism. Those decisions also shaped the state of mind and conceptual groundwork for a revolutionary new approach toward the understanding of the workings of celestial and terrestrial bodies alike.
One may, therefore, look with Duhem  at the decree as the starting point of a new era in scientific thinking, provided it is kept in mind that the decree expressed rather than produced that climate of thought which Whitehead once rightly presented as the most crucial ingredient for the eventual creation of modern science. His views were expressed in a long passage which, because of its classic Whiteheadian stamp, deserves to be quoted in full:
I do not think, however, that I have even yet brought out the greatest contribution of medievalism to the formation of the scientific movement. I mean the inexpugnable belief that every detailed occurrence can be correlated with its antecedents in a perfectly definite manner, exemplifying general principles. Without this belief the incredible labours of scientists would be without hope. It is this instinctive conviction, vividly poised before the imagination, which is the motive power of research: – that there is a secret, a secret which can be unveiled. How has this conviction been so vividly implanted on the European mind?Half a century has passed since these words startled a distinguished audience at Harvard University and indeed the whole intellectual world. The magnitude of the shock merely corresponded to the impenetrable density of a climate of opinion for which the alleged darkness of the Dark Ages represented one of the forever established pivotal truths of the "truly scientific" interpretation of Western intellectual history. Not being a professional historian of science Whitehead could not be blamed for not having perused the first five volumes of Duhem’s Système du Monde. Its extraordinary wealth of documentation might have very well raised in Whitehead’s mind some doubts about the validity of the concluding phrase of his long statement. At any rate, the spectacular flow of studies An medieval science touched off by Duhem’s monumental work provided among other things ample evidence that the medieval faith in the scrutability of nature had its logical justification in the medieval theology about Creator and creation, and that the faith in the possibility of science is a most conscious derivative from the tenets of medieval theology on the "Maker of Heaven and Earth."
When we compare this tone of thought in Europe with the attitude of other civilisations when left to themselves, there seems but one source for its origin. It must come from the medieval insistence on the rationality of God, conceived as with the personal energy of Jehovah and with the rationality of a Greek philosopher. Every detail was supervised and ordered: the search into nature could only result in the vindication of the faith in rationality. Remember that I am not talking of the explicit beliefs of a few individuals. What I mean is the impress on the European mind arising from the unquestioned faith of centuries. By this I mean the instinctive tone of thought and not a mere creed of words.
In Asia, the conceptions of God were of a being who was either too arbitrary or too impersonal for such ideas to have much effect on instinctive habits of mind. Any definite occurrence might be due to the fiat of an irrational despot, or might issue from some impersonal, inscrutable origin of things. There was not the same confidence as in the intelligible rationality of a personal being. I am not arguing that the European trust in the inscrutability of nature was logically justified even by its own theology. My only point is to understand how it arose. My explanation is that the faith in the possibility of science, generated antecedently to the development of modern scientific theory, is an unconscious derivative from medieval theology. 
 Le système du monde, vol. VI, p. 66. Duhem offered the last five volumes of his monumental opus as proof of the proposition that modern science "was born, so to speak, on March 7, 1277 from the decree issued by Monseigneur Étienne, bishop of Paris." By this Duhem meant that the decree decisively reinforced, mainly at the University of Paris, a train of thought leading ultimately to the formulation of a new (classical) physics.
 Science and the Modern World: Lowell Lectures, 1925 (New York: The Macmillan Company, 1925), pp. 17-18.
[quoted from Science and Creation by S. L. Jaki pp 229-231]