See Fletcher and Fletcher-Empress. The Empress engine was designed by Charles A. Fletcher.

-There was the five-cylinder rotary giving 50 hp. By the way, being very similar to Gnome, and even using some of their patents, the matter came to court.

“A 5-cylinder Empress” (PiP)

-They also made a seven-cylinder engine.

From Appendix 10: The index of this publication mentions two radial engines manufactured by this brand, the 5-cylinder and the 7-cylinder. Now we see a 7-cylinder engine in an ad of the time.

"Empress advertisement"
(from Aviation Ancestry.co.UK)
 

-The name of Empress that appears in the Index of this work, turns out to be also "The Empress Motor Car & Aviation Co. Ltd".