Vitamin E was discovered in 1922 by Herbert McLean Evans and Katharine Scott Bishop and first isolated in a pure form by Evans and Gladys Anderson Emerson in 1935 at the University of California, Berkeley. Because the vitamin activity was first identified as a dietary fertility factor (in rats) it was given the name "tocopherol" from the Greek words "τόκος" birth, and "φέρειν", to bear or carry meaning in sum "to carry a pregnancy," with the ending "-ol" signifying its status as a chemical alcohol. George M. Calhoun, Professor of Greek at the University of California, was credited with helping with the naming process. Erhard Fernholz elucidated its structure in 1938 and shortly afterwards the same year, Paul Karrer and his team first synthesized it.