Georges Henri Joseph Édouard Lemaître was a Belgian Catholic priest, theoretical physicist, mathematician, astronomer, and professor of physics at the Catholic University of Louvain. He was the first to theorize that the recession of nearby galaxies can be explained by an expanding universe, which was observationally confirmed soon afterwards by Edwin Hubble. He first derived "Hubble's law", now called the Hubble–Lemaître law by the IAU, and published the first estimation of the Hubble constant in 1927, two years before Hubble's article. Lemaître also proposed the "Big Bang theory" of the origin of the universe, calling it the "hypothesis of the primeval atom", and later calling it "the beginning of the world".

The Catholic University of Leuven or Louvain was founded in 1834 in Mechelen as the Catholic University of Belgium, and moved its seat to the town of Leuven in 1835, changing its name to Catholic University of Leuven. In 1968, it was split into two universities, the Katholieke Universiteit Leuven and the Université catholique de Louvain, following tensions between the Dutch and French-speaking student bodies.