I wouldn’t classify either of these types as rotunda. Morris’ Troy type reminds me a lot of Schweynheim and Pannartz’s Roman type. Like the contemporary Ashendene Press Subiaco type, based on S&P’s first type, it is an attempt to capture something of the historical transition from blackletter to humanist type that took place in the first few years of printing in Italy. If you add to these two types the Doves Press roman, you have a kind of historical recreation, culminating in the Jensonian roman.

Morris’ Troy type reminds me a lot of Schweynheim and Pannartz’s Roman type

And when I looked for examples of that in Chappell’s book, damned if it’s not just as you say— loads of similarities. Chappell’s book has been really helpful for me, but maybe he’s forced this comparison.

I’m not a big one for classification, but there are some apparent structural differences in the 2. See d, e, a . I think Morris was hoping to open up the design and make it more readable to an English-speaking audience, one not used to reading blackletter. Hence the more latinised shapes of d, a, w, etc.

Morris’ Troy was an effort to revive the look-and-feel of early printing in the machine age. Morris was interested in all the aspects of book arts, but was English and not known as a letterer. Koch was a calligrapher, a German one, who was thoroughly familiar with the various historical blackletter styles. Koch’s various blackletter types derive directly from calligraphic styles, ones he practiced and read. The Troy type was a little like Morris’ Golden type; a mimic intended to convey an archaic feel in books produced by Morris’ workshop. In contrast, Koch not only practiced many blackletter hands, but cut a few types himself in addition to the ones Klingspor had cut from his designs.

Chappell (Warren, not William) says it himself, Troy “imitates models on which it was based”.

You might say Morris was attempting to reproduce the superficial characteristics of early printing in his work. There is an element of kitsch or parody to his types. Koch knew the structure and history of the hands he based his types on, and was successful at translating those styles directly into printing types intended for his contemporaries.