This was actually in 1345 and was much more of a massacre than the famous one in Chicago in 1929 where I believe 7 men died.
In the Liverpool massacre, at least 27 died. The tale relates to a feud between the Radclyffe and Trafford families. The Radclyffes did most of the killing it seems. Sir John Radclyffe and others were arrested but later pardoned on condition of fighting for the King for a year at their own expense. Sir John radclyffe died in 1362.
It would be great fun to re-enact this massacre on the streets of Liverpool !! Bound to bring the tourists in to see the mock battle.