The first President of the IAU, Benjamin Baillaud

Benjamin Baillaud was appointed president of the First Executive Committee of the International Astronomical Union which met in Brussels during the Constitutive Assembly of the International Research Council (IRC) on July 28th, 1919. He served in this position until 1922, at the time of the First General Assembly of the IAU which took place in Rome, May 2-10. At that time, Baillaud was director of the Paris Observatory. He had previously been director of the Toulouse Observatory for a period of 30 years and Dean of the School of Sciences of the University of Toulouse. He specialized in celestial mechanics and he was a strong supporter of the "Carte du Ciel" project; he was elected chairman of the permanent international committee of the Carte du Ciel in 1909. He also was the founding president of the Bureau International de l'Heure (BIH) and he was directly involved in the coordination of the ephemerides at an international level. In this paper, we present some of his activities, particularly those concerning international programmes, for which he received international recognition and which eventually led to his election in 1919 to the position of first president of the IAU. We also briefly recount the very first meetings and years of the IAU.