I agree that the same person did both the Lancelot and the Cary-Yale, and that it probably came from the Bembo workshop. I just think that's all we know. Can you show me anything definitely of Bonifacio's (not, of course the Lancelot or the cards, both of which are in question) that is similar?
You can find where in the thread there are posts using particular words by putting the word in the "search this topic" box at the start of the thread. Then scroll down to the earliest post and work your way up. At least that's how I find things.
I actually presented my Grail argument first on Aeclectic, at
http://www.tarotforum.net/showpost.php? ... stcount=20, using Lancelot among other things. That's where this "Investigation" thread started. At that time I attributed both the CY and the Lancelot to Bonifacio Bembo; but Welch has convinced me that such an attribution would be premature (see
viewtopic.php?f=11&t=365&start=120#p5200, find "Welch").
I like your theory about the knight, except that I don't understand why there would be two people in the ferryboat. Perhaps there is a private story. Or else it is a modified version of a card done for an earlier deck, originally without the person sitting, modified for the specific purpose of designating a publically identifiable person, such as Piccinino. Do you know when Filippo did his improvements to Cusago, and when he started going by canal? That would give us the earliest possible date for a version of the card with your interpretation. If at some point he stopped going, due to physical difficulties or increased reclusiveness, that might suggest that a card with that interpretation would not have been initiated after that date. I see on one of your links that he didn't build it, just added floors and decorations. It was built in 1354. I see on your other link the date 1423 as a possible year for the initiation of improvements, when Bruneleschi was called in (if I read the Italian correctly). If so, that gives 1423 to some unspecified later date as the time your theory would apply to some version of the card. Your reference to the canal trips is still in the 1420's. That seems to me to be a reasonable time for an early version of the card.
I don't see why, so far, your Visconti theory excludes my Grail theory. I would phrase it this way: the Grail Knight is Filippo, going to his Grail Castle, Cusago, a place not of this world. Filippo loved Grail stories and French romances generally, I gave the reference much earlier in this thread (
viewtopic.php?f=11&t=365&start=10#p4604, third paragraph) as well as in the post on Aeclectic. I would not be surprised if Filippo commissioned the Lancelot, although since there was a Grail fresco sequence in Mantua, it might have been the Gonzagas; and since there was a similar Knight-and-Lady fresco sequence, with castles on hills, it might have been Piero Maria Rossi, whose mother (or wife?) was from Cremona (as I discussed in the post just referred to).
At the same time the Knight in the card could also be, in a new interpretation of an old design, Francesco Sforza rescuing Piccinino from a tight spot. I love the word "polysemous." Then the card could be either 1441-1442, for Francesco's wedding, or post-1450. Sforza would have been able to display the viper on his banner either time, if that's what's there. The incident that Trionfi refers to, where Piccinino sneaks out of his predicament in a sack, puts him in a rather ridiculous light. For that reason, 1441 would not have been the wisest time for Filippo to commission such a card. Piccinino might have been offended and left Filippo's service at his first opportunity. Of course that's just what Piccinino did, and Filippo was a pretty insensitive guy, so it's possible. Post-1450, Piccinino and Sforza were rivals, and the Piccinino family in Lombardy would have preferred their man to be in charge rather than Sforza. So as anti-Piccinino propaganda, Piccinino ingloriously in the bottom of the boat, and Sforza to the rescue, makes good sense for Francesco to remind people of in a card whose theme is Glory. Anyone with the name Piccinino continued to be a source of humor. As late as 1471, Galeazzo instructed that that Alesseio Piccinino "be depicted such that a stag has thrown him from his horse, and he is raising his legs to the sky in as attractive a manner as possible." Such, Lubkin notes, was Galeazzo's "perverse humor" (
A Renaissance Court, p. 107, in Google Books).