hi Jim,
you are new here ... so I just inform you about some conditions. I try to keep it simple, in reality it's really complicated.
There are two alternative models of Tarot development, which are important for some of the speakers here.
Theory 1: assumes the existence of a Tarot similar Trionfi deck with 4x14+22-structure "very early". Very early means usually 1437-1440.
This is accepted "more or less" by Ross Caldwell, by Michael J. Hurst, by Robert Mealing
Theory 2: assumes the existence of a Tarot similar Trionfi deck "very late". As earliest example of the existence of 4x14+22 is accepted the Boiardo Tarocchi poem (internally dated 1487), but it isn't excluded, that earlier "something like this" existed before.
This is accepted more or less by MikeH (Micheal S. Howard) and myself.
Theory 1 isn't very complicated. It's just a more intensive reading as that, which was already stated by Michael Dummett, Thierry Depaulis and Decker in "Wicked Pack of Cards", who said, that "around 1450" Tarot game was settled to a standard.
Theory 2 in contrast is very complicated, as it really has to deal with the decks, which are taken as "from before 1487". It sees in the development decks with 14 trumps, decks with 16 trumps and decks with 20 trumps.
16 Trumps
the theory assumes a stronger relation to chess, cause Chess uses 16 figures.
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1. The Michelino deck (before 1425) has 16 trumps and totally 16 cards.The birds are suits. Interestingly this rather strange deck was later (in 1449) by a contemporary speaker addressed as a Ludus Triumphorum, which throws a strong doubt about the use of the word "Trionfi" or "Ludus Triumphorum". It contradicts the interpretation, that Trionfi cards were always similar to later Tarot cards.
http://trionfi.com/0/b/
2. The Cary-Yale deck (assumed to be possibly from 1441, but at least before 1447) has clearly 16 suit cards and remaining are 11 trumps, from which 4 (3 theological virtues + Fame) are not part of the usual Tarocchi system. The Theory 2 assumes, that the 11 cards are the fragment of an earlier 5x16-composition. A reconstruction attempt can identify 14 of 16 cards and that these would fit with a Chess idea.
See:
http://a-tarot.eu/pdf/cy-jpg.jpg
3. The Charles VI (by Theory 2 assumed to be from Florence and from "around 1463") has 16 trumps and 1 court card. Theory 2 assumes, that the trumps are complete and not a fragment of a deck with 22 special cards. As in the case of the Cary-Yale the 16 trumps can be sorted to figures of the game of chess.
See:
http://a-tarot.eu/pdf/ch-jpg.jpg
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14 Trumps
The theory assumes, that a deck with 5x15 structure took some influence
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1. A document of 1.1.1441 in the Ferrarese account books reports a gift of 14 pictures (it's not clearly related, that these are playing cards) for Bianca Maria Visconti, daughter of Filppo Maria Visconti (well known for playing experiments). Bianca Maria is as a guest in Ferrara for an half year. One option iof the given tim is, that Bianca Maria might marry Leonello, heir of Ferrara (and not Francesco Sforza)
http://trionfi.com/0/e/00b/
Arguments:
a. The painter of the pictures is Jacopo Sagramoro, earlier already playing card painter, and later Trionfi card painter.
b. Leonello is a year later commissioner of Trionfi cards.
c. The first of January is traditionally a date for gambling, so also connected to playing cards
d. The pictures might have been a preparation for a future Trionfi deck, for instance for a marriage between Leonello and Bianca
e. The first Trionfi deck currently known appeared in September 1440, so just short before the scene o 1.1.1441
f. The court of Ferrara is in this time full of young persons (children of Signore Niccolo), and playing cards were often connected to rather young people
http://trionfi.com/0/d/
2. The Pierpont-Morgan-Bergamo has for its extant 20 trumps 2 different painters. One painted 14 (and all the pip cards), and the other painted 6. This fact was earlier interpreter with loss and damage of some cards and with their replacement.
However, the composition of the two different groups follows some internal logic, and it's very unlikely, that this composition was generated by accident. So Theory 2 assumes, that the 6 cards were not replacements, but 6 added cards at a later time.
According this the original deck was 5x14 ... and this observation and its interpretation was later called "5x14-theory".
http://trionfi.com/0/f/11/
3. A document in Ferrara in 1457 speaks about the production of two Trionfi decks. The document notes, that the decks contain 70 cards ... which means, that this information contradicted the assumption, that these decks had 78 cards (which they should have had, if they were already similar to Tarot cards), but it is in harmony with the 5x14-theory.
It's the only document, which really tells us something about the number of the Trionfi cards. Well, maybe beside the Michelino deck, which speaks of 16 trumps. A "22" appears nowhere in the documents, but it's clear with the Boiardo Tarocchi poem, which in its style is very different from the usual Tarot.
http://trionfi.com/0/e/16/
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20 trumps
Only known from later development
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1. According the 5x14-theory the second painter added 6 cards. Some research led to the assumption, that this likely happened in the year 1465, at the opportunity of the wedding preparations and connected bride journey of Ippolita Sforza in May.
2. We have Minchiate documents in 1466, 1470/71 and 1477. In our opinion this indicates an expansion of an earlier order of the trumps and some changes in the game a short time before. If Minchiate had already at the begin of its development the state of 41 cards, is not clear.
http://trionfi.com/0/p/09/
3. There is a lot book of Lorenzo Spirito produced in 1482, which in his divination scheme uses a 20x20x20x20 structure (with connected pictures), which has some similarity of the structure of Minchiate, Possibly this lot book indicates, that the Minchiate had at least had reached 40 trumps.
viewtopic.php?f=11&t=442&hilit=lorenzo+spirito
4. There is a relative new idea from Franco Pratesi, which possibly might relate the Rosenwald Tarocchi to the early 1460s and to Minchiate. This is generally not accepted as very sure, but might be a possible explanatio. It considers the possibility of an early Minchiate with 96 cards.
http://trionfi.com/rosenwald-tarocchi-sheet
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I just summarized the much more complicated researches. I hope it helps you to have some orientation in the discussion.