It was at the dawn of the 18th century that “hay fever” was first identified as such. The symptoms were exhaustively described in all their aspects by a physician who was particularly well-informed as he himself suffered from this catarrhal condition every year in the flowering season. But it then took many other discoveries to understand the pathophysiology, starting by identifying the role of pollens, conceptualizing the principles of the reaction and giving it the name of allergy, and then developing the first screening and identification tests of individual sensitization. This historical article describes the major discoveries and key actors that contributed to the current knowledge of pollinosis and, more broadly, of allergic rhinitis.