Hi all!
What I can add is that this order is the eldest order in Bulgaria, established by the first Bulgarian constitution from 1879 (Tirnovo constitution) and was created by the first prince Alexander von Battenberg on January 1st, 1880. It`s official day is on April 17th and from 1891 on May 6th. Up to 1909 was the senior Bulgarian order, replaced by the St.St. Cyril and Methodius order. The first grade was awarded only 5 times.
Extremely rare is the 3rd grade, but as Bulgarian armies fought against the Nazi armies between September 1944 and May 1945, there were a dozen of them awarded. after December 1946 the crown was replaced with a wreath (the republican version). There is an uncomplete list in the Royal papers in the Central state archive in Sofia, that is not published.