First Among Equals Meaning

Example : 1986, Robert Williams, "Review of First Among Equals: Prime Ministers in Westminster Systems by Patrick Weller," Pacific Affairs, vol. 59, no. 2, p. 386,  The value of First Among Equals lies in its attempt to set out systematically the major roles played by prime ministers, and to provide insights by a detailed comparison of the same office in four countries.2003, H. Y. Sharada Prasad, The Book I Won't be Writing and Other Essays‎, page 40:  I wonder whether Margaret Thatcher, Harold Macmillan, Winston Churchill, Lloyd George, Benjamin Disraeli and William Gladstone (going back in time) thought of themselves as mere firsts among equals.