Nevron Kicking Incident
Re-enactment of the kicking many years later
Basically Nevron Dreadstar kicked Lief, who was a young (early teens) kid at the time, dropped his belts for a time as penance, and was eventually reinstated.
Some time after that, Ivar Nefarious made a set of collectible trading cards for amtgard knights based on the card game Magic the Gathering. The card for Nevron in this game read "summon boy-kicker". This apparently greatly angered Nevron, who was upset that his shameful act of the past was brought to light again, at a time when it seemed buried and mostly forgotten.
At a spring war shortly after this, one of Ivar's squires, Zol brought his Castle to the event, and while there it was defaced with magic markers, some said in retaliation at Ivar for the cards. This caused a great brou-ha and the end result was many people who would have never heard about the original incident ended up finding out about it.
Some attribute Lief's fighting prowess to having been kicked in the chest by Nevron at a young age.