[Knitting A Conundrum]

The catholic encyclopedia has this history:
http://www.newadvent.org/cathen/14714c.htm

[Aquinasfan]

Thanks. It's interesting to me that the three-tiered crown came into use in the Scholastic era.

The first notice of three crowns is contained in an inventory of the papal treasure of the year 1315 or 1316.

The symbolism of the crown makes sense to me, and can serve a useful purpose as a teaching tool. I also personally prefer the bishops' crowns of the Eastern Rites to the mitres of the Latin Rite.