→Subscribe for new vide→“Yf they say the mone is blewe/We must believe that it is true.” It appears to be a reference to priests at the time making statements and expecting the average person to believe they were true, regardless of how ridiculous the statement was. This is something like the original usage of the “moon is made of green cheese”, in that case referring to the fact that only fools or gullible people would believe that.
Want the text version?: http://www.todayifoundout.com/index.php/2013/06/the-origin-of-the-phrase-once-in-a-blue-moon/
Sources:
http://www.phrases.org.uk/meanings/once-in-a-blue-moon.html
http://en.wikipedia.org/wiki/Blue_moon
http://en.wikipedia.org/wiki/Farmers%27_Almanac_full_moon_names#Farmers.27_Almanacs
http://www.skyandtelescope.com/observing/objects/moon/3304131.html?showAll=y&c=y
http://www.ips-planetarium.org/?page=a_hiscock1999
http://science1.nasa.gov/science-news/science-at-nasa/2004/07jul_bluemoon/
http://en.wikipedia.org/wiki/Far_side_of_the_Moon
Image Credit:
https://upload.wikimedia.org/wikipedia/commons/b/bb/Zeusandhera_-_Lunar_Spiral_Cycle_(by-sa).jpg
https://upload.wikimedia.org/wikipedia/commons/9/99/Northwest_Crown_Fire_Experiment.png
