Brian Dobson's Chapter on the praefectus castrorum (link to free download)

I'm having to offer this source as follows because Facebook is, apparently, beginning to hunt down and remove anything from my blog site that has quoted material - whether I have permission to quote said material or not.

Dobson's work is fundamental to our understanding of the evolution of the rank and role of the praefectus castrorum in the Roman army.  I highly recommend this source.  The download is free. The relevant discussion starts on p. 413.

https://pdfcoffee.com/dobson-the-significance-of-the-centurion-and-primipilaris-in-the-roman-1974-pdf-free.html

To supplement this book, see Davenport's treatment of the subject here:

https://mistshadows.blogspot.com/2022/11/l-artorius-castus-praefectus-castrorum.html

I have the permission of Davenport for providing some of his study.  Extensive correspondence will prove this to be so, should Facebook have a problem with this post as well.