Raymond Martin Marie Ghislain, Baron Lemaire (Uccle, 28 May 1921 - Woluwe-Saint-Lambert, 13 August 1997) was an art historian and an architectural historian, a leading expert in conservation and professor at the Catholic University of Leuven and later at the KU Leuven and the Université catholique de Louvain in Louvain-la-Neuve.
In 1948, he obtained a doctoral degree in Art History and Archaeology with a dissertation on the origins of Brabantine Gothic, L'Origine du style gothique en Brabant.
He became renowned for the restoration of the Grand Béguinage in Leuven, where he put into practice the Venice Charter, of which he was the main editor.
He took also part in other urban projects: He took also part in projects for new buildings, as designer or counsel, often in collaboration with the architects Robert Vandendael, Daniël Depoorter, Simon Brigode, Marc Dessauvage, He was also the initiator of the extensive series of books with the inventory of the Belgian architectural inheritance, along a methodology which he developed.
With Piero Gazzola he founded in 1965 ICOMOS, the International Council for Monuments and Sites, an NGO linked with UNESCO.
He attained international recognition thanks to his activities as an expert and counsellor for important restorations and numerous renovations.
Most archives of Lemaire's office, including numerous architectural drawings, are kept in the Central Library of the University of Leuven, while his slides are kept in the RLICC.