Ginevra de' Benci

Ginevra de' Benci (Born 1457) was a lady of the aristocratic class in 15th century Florence, admired for her intelligence by Florentine contemporaries. She is the subject of one of only about 17 existing paintings attributed to Leonardo da Vinci. The oil-on-wood portrait was permanently acquired by the National Gallery of Art in Washington, D.C., USA, in 1967 for US$5 million paid to the Princely House of Liechtenstein, a record price at the time. This portrait is currently the only painting by Leonardo in the Americas.

You can also see it on a high resolution zoomable image at NGA.

Matila Ghyka

Prince Matila Costiescu Ghyka (September 13, 1881–July 14, 1965), was a poet, novelist, mathematician, historian, and diplomat, and the Romanian Plenipotentiary Minister in the United Kingdom during the late 1930s and until 1940. Recently, a good friend (I.D.) - which continuously surprise me - put him under my eyes.
In his book 'The Geometry of Art and Life' pleads for a mathematical theory of aesthetics talking about the fascinating relationship between geometry, aesthetics, nature and the human body. This classic study probes the geometric interrelationships between art and life in discussions that range from Plato, Pythagoras and Archimedes to modern architecture and art, flowers, shells and marine life, the human face and much, much more. Also explored: the Golden Section, geometrical shapes on the plane, geometrical shapes in space, crystal lattices and many other fascinating topics.

You can read more about him here (or in romanian). Also, there were published recently 3 articles in romanian: Matila Ghyka, everywhere and nowhere, Following the traces of Matila C. Ghyka and Matila Ghyka in America.