Muriel Rukeyser (1913–1980) poet and political activist
Source: The Life of Poetry (1949), p. 222
Found attributed to Michelangelo in non-specialist publications as early as 1929 https://books.google.com/books?id=-0YhAQAAMAAJ&dq=If+people+knew+how+hard+I+had+to+work+to+gain+my+mastery%2C+it+would+not+seem+so+wonderful+at+all.&focus=searchwithinvolume&q=michelangelo, but no source is known. Not found in any known biography of Michelangelo. <br class="br">Disputed
Muriel Rukeyser (1913–1980) poet and political activist
Source: The Life of Poetry (1949), p. 222
Alfred, Lord Tennyson The Sisters
The Sisters, reported in Bartlett's Familiar Quotations, 10th ed. (1919)
Gerhard Richter (1932) German visual artist, born 1932
after 2000, Gerhard Richter: An Artist Beyond Isms' (2002)
Michael Nava (1954) American writer
Source: Henry Rios series of novels, Rag and Bone (2001), p.174
Pope Sixtus V (1520–1590) pope
On Queen Elizabeth I of England, in 1587; reported in Emil Reich, Woman Through the Ages: Volume 2 (1908), p. 38. Alternately reported without the phrase "each other" and ending with "would have ruled the whole world".
Attributed
Pierre-Auguste Renoir (1841–1919) French painter and sculptor
Benicka (1980) commented:
The frescoes of Raphael and the Pompeian murals that he saw there definitely confirmed what Renoir had begun to feel about his own art; that it was becoming too amorphous in character and was weak in design.
undated quotes
Source: ''Renoir'', by A. Vollard, Paris, 1920, p. 135; as quoted in: Corinne Benicka (1980) Great modern masters. p. 130;
The Mother (1878–1973) spiritual collaborator of Sri Aurobindo
As quoted in "Paris (1897-1904)", and in Bulletin, Volume 53 by the Sri Aurobindo International Centre of Education (Pondicherry, India) http://books.google.co.in/books?id=VMzWAAAAMAAJ