Frithiof Niordson was born in 1922 of a Russian mother and a Swedish father. He studied at KTH in Stockholm and then did a PhD with William Prager at Brown University in the United States; however, from 1958 onwards Frithiof Niordson was a full professor at the Technical University of Denmark (DTU). His scholarly research covered a wide range of topics in applied and computational mechanics, including vibrations, stability, inverse eigenvalue problems, the theory of plates and shells and structural optimisation. He also played major roles both in Denmark and internationally, being the driving force behind the development of the Danish Center for Applied Mathematics and Mechanics (of which he was secretary from its inception in 1969 until 1992) and serving with great distinction as Secretary-General (1968-1976), President (1976-1980) and Vice-President (1980-1984) of IUTAM. He had many international collaborators and was instrumental in enabling younger Danish mechanics scholars to develop their international careers. He will be sorely missed.