Williams College color 

"Early in the summer of 1865 the Williams baseball team were about to leave Williamstown to play the final game of the series against Harvard, and just before our departure two young ladies--my sister* and my cousin--who were very much interested in the result of the game, learned that while Harvard had adopted magenta as its College color, Williams was without any.  They hurriedly purchased some royal purple ribbon and made small rosettes out of it, and pinning one on each member of the team, said "Let this royal purple be the Williams color, and may it bring you the victory over Harvard."

"The royal purple joyfully floated from the mast-head that next day, for the game was handsomely won. This victory gave Williams the championship in the intercollegiate contests between Princeton, Harvard and Williams, and the royal purple has ever since been the banner under which Williams has won so many brilliant victories."

Eugene M. Jerome (Williams Class of 1867) in The Williams alumni review, Apr. 1910.

* Eugene's cousin was Jennie Jerome who would became Lady Randolph Spencer Churchill, mother of Winston Churchill

Williams uses PMS 267 for print, and #330066 for the web. Technically, Williams has only one college color, but it is often paired with a gold or yellow to differentiate Williams publications and uniforms from those with Amherst's colors of purple and white.

College Nine, 1865
The "College Nine" of 1865