Quote in a letter to his friend Peiresc, 18 Dec. 1634; as cited by Simon Schrama, in Rembrandt's eyes, Alfred A. Knopf - Borzoi Books, New York 1999, p. 402 
1625 - 1640
                                    
Peter Paul Rubens: Quotes about effort
Peter Paul Rubens was Flemish painter. Explore interesting quotes on effort.
                                        
                                        Quote of Rubens, in his letter to Count Annibale Chieppio (minister of the Duke of Mantua), February 2, 1608; as cited in Rembrandts Eyes', by w:Simon Schrama, Alfred A. Knopf, Borzoi Books, New York 1999, p. 130 (LPPR, 42) 
Rubens reports in this quote about the overdoses of light, falling upon his recently-made altar-painting 'Virgin and Child Adored by Angels', (Rome, Santa Maria, Vallicella), 1607 which is fading the colors for the viewer. 
1605 - 1625
                                    
                                        
                                        In his letter to Dr. Johannes Faber, 10 April 1609; in De Zuidnederlandse immigratie, 1572-1630, J. Briels, Haarlem, 1978, p. 43-44. 
one of Rubens' good former companions during his stay in Rome c. 1604-1607 was Dr. Johannes Faber, the 'Aesculapius', who had cured his pleurisy then 
1605 - 1625