Hello Michel,
i think the standard is referred to one Lorenzo il Magnifico's emblems, the so called "broncone" (like trunk), a re-flowering laurel (laurel = Lorenzo) plant, which alludes to re-birth an new vigor in Medici's family under Lorenzo and his brother Giuliano. The girl could refear to Florence. The laurel therefore symbolized olso a sort of continuity, triumph and immortality of the Medici dynasty.
In some verses from "La giostra" by Luigi Pulci, the banner is described as divided into two part, one white and the other light blue, which showed the "Le Temps Revient" motto above a rainbow and under the sun and below, Lucrezia Donati (Lorenzo's lover...perhaps), in a blue tunic, intent on preparing a laurel wreath.
Some interesting reconstruction about this tournament called "giostra romanza" (1469) can be find in this two essays:
Scalini, Mario, Il "ludus" equestre nell'età laurenziana, in
Le Temps revient - Il tempo si rinnova, 1992, pg.75-102
Ventrone, Paola, La giostra "romanza" di Lorenzo del 1469, in
Le Temps revient - Il tempo si rinnova, 1992, pg.167-187
The MB flats become, i think, from some Mario Venturi renaissance miniatures:
http://www.parvimilites.it/03_051rinitaliano.htmlAngelo, really great paintjob! I love your tins!