Pathminder appears to have predated Norton Commander by a couple of years, tough I've never used it.
As a former Amiga user I'm compelled to argue the ones who perfected this was Disk Master and Directory Opus ;) Directory Opus is still available, now for Windows, but looks nothing like the early versions and frankly I don't like the modern versions.
Personally I preferred Disk Master II [1], which by default kept the two directory listings and a command palette, but instead of making them fixed like most file managers of the era (including the previous version of Disk Master [2]), the directory listings and the command palette were all windows, and you could configure the layout and which commands were included so you could e.g. have it execute your own scripts and the like (I'm sure most gui file managers have that today - at the time it wasn't at all ubiquitous).
EDIT: AmigaOS also had CLImate which used a similar two-pane system, and which came out about the same time as Norton, but CLImate was very primitive and marred by the developers seemingly wanting to make full use of the available fonts provided with AmigaOS - note the at least three different fonts on the buttons [3] - and way too much padding taking space from the directory listings.
[1] http://myplace.frontier.com/~jodytierney/dm2.html (click on the image for a bigger version) shows a customised DM II setup.
[2] https://www.pinterest.co.uk/pin/411586853453284894/
[3] http://eab.abime.net/attachment.php?s=2b3fea62abf55fc52bffc7...