Q:

Single word for "self-mastery and fortitude in the face of boorish behavior"

I am looking for a word that is defined thusly: 

the self-mastery and fortitude with which a person conducts himself in the face of life's vicissitudes and the boorish behavior of others. 

A:

This apparently comes from an article called A Nation of Cowards by Jeffrey R. Snyder, originally published in the Fall, '93 issue of The Public Interest.   It is archived at the website for National Affairs, Inc. (its parent company, I think). 
The full quote is:

"Dignity" used to refer to the self-mastery and fortitude with which a person conducted himself in the face of life's vicissitudes and the boorish behavior of others.  

Hope this helps!