Something interesting I stumbled on.

Tarot cards
Medieval tarot cards included a card showing a woman wearing a papal tiara and known as the Popess or Papess or the High Priestess. The meaning and symbolism of the card is uncertain. The crowned woman has variously been identified as Pope Joan (a woman who according to a medieval and later Protestant myth had disguised herself as a man and been elected pope; some cards also show a child, and the Pope Joan myth pictured her as found out when she gave birth during a papal procession), as Mary, Mother of God, or even as Cybele, as Isis, or as Venus. Cards with a woman wearing a papal tiara, produced during the Protestant Reformation, and apparent images of "Pope Joan" and her child, have been seen as a Protestant attempt to ridicule the office of the papacy and the Catholic faith.
The papal tiara, however, disappeared from later cards, which showed the Popess wearing more standard medieval female headgear. The tarot cards also contained a representation of the pope, in some cases crowned with a papal tiara.

Blessed be

what would a papal tiara would look like back then?  Would you say it looks like The Hierophant's trible crown or something close to that because he is sometime called the "pope"?
what would called the headdress she is wearing now in RW deck.

I will compile a doc with all the tiara's I managed to retreive pics for. The High Priestees's headdress is The Moon in differing stages. But in those days the papess also wore a three tier crown or Tiara.

I'll try and attach a pic
Look at the Papal mass, on an "shelflike" area you can see a number of Tiara's displayed.

Blessed be

Doesnt the three tier tiara/crown simply stand for the Holy Trinity - Father, Son and Holy Spirit?

very interesting. thanks for taking the time to post.  
like Cedars i read that the three tier stands for the trinity too.