"Fra Serafino da Imola tells us unequivocally that the ambush in which Buonterzo ended his turbulent life in March of that year was of Bellarion's planning." [Chapter 3.I]

Fra Serafino should have dealt a little more in equivocation, since in fact Ottone Buonterzo (aka Ottobono Terzi) died, extremely gruesomely, in May (not March) of 1409.