I found a photo of bike polo from 1921. Playing in the street, knocking each other off their bikes, small ball, and the right kind of mallets. Evidence that hardcourt bike polo has been played much further back in history than the PNW wants us to believe.

Click the image to see full size.

Simply titled “Bicycle Polo” this is from the National Photo Company Collection (Library of Congress)
The date is listed as 9/13/1921 but the location unknown to me. Odds are it’s not Seattle.

Also, Kev’s Grandad tells about playing bike polo in the streets of Ireland in the 1930′s.