I have compiled a (very) short list of some of the important Welsh scientists and mathematicians throughout history. They are in no particular order.

Alfred Russel Wallace
Born 8 January 1823, Usk, Monmouthshire, Wales.
Died 7 November 1913 (aged 90) Broadstone, Dorset, England.

He independently conceived the theory of evolution through natural selection, which prompted Charles Darwin to publish his own ideas in On the Origin of Species.

Brian David Josephson
Born 4 January 1940 Cardiff, Wales.

He is known as a pioneer of the theoretical undesrstanding of superconductivity. He was awarded 1/2 share of the 1973 Nobel Prize for Physics for “his theoretical predictions of the properties of a supercurrent through a tunnel barrier, in particular those phenomena which are generally known as the Josephson effects”.

William Jones
Born 1675, Llanfihangel Tre’r Beirdd, Isle of Anglesey
Died 3 July 1749

He proposed the use of the symbol π (the Greek letter pi) to represent the ratio of the circumference of a circle to its diameter.

Robert Recorde
Born ca. 1512, Tenby, Pembrokeshire, Wales
Died 1558 London, England

He introduced the “equals” sign (=) and also the “plus” sign(+) in 1557.

Elmer Gethin Rees
Born 1941 Llandybie, Carmarthenshire, Wales

A mathematician who has published in a diverse range of areas including topology, differential geometry, algebraic geometry, linear algebra and Morse theory.

Lyndon Evans
Born 1945 Aberdare Wales

Project leader of CERN’s Large Hadron Collider.

Bertrand Arthur William Russell
Born 18 May 1872 Trellech, Monmouthshire, UK
Died 2 February 1970 (aged 97) Penrhyndeudraeth, Wales, UK

He co-authored, with A. N. Whitehead, Principia Mathematica, which was an attempt to set all mathematics on the basis of logic.