The gonfanon is flown from a vertical staff and has tails on the fly. The difference between a gonfanon with long tails and a standard is that a gonfanon displays the device on the non-tailed area, and the standard displays badges down the whole length of the flag.
Definition from The Oxford English Dictionary.
Christ holding a red banner. 1100?
Charlemagne giving Roland a red gonfanon.
Seals of the landgrave Conrad II of Thuringia, about 1234. Banner and gonfanon.