Answer Wiki. Wikipedia has a fairly good summary - Modern art - defining it broadly as art from much of the second half of the 19th century through nearly 3/4 of the 20th. There's also a piece on Modernism in the arts from the mid-19th century through the present.
Another major difference that can be seen between Cajun and Creole is in their foods. The food of Creole is Afro-European with some French flair. On the other hand, Cajun foods have a French influence. One can also see that the two sects of people practise and love different music.
Cajun French and Creole French are not the same thing...both are interesting dialects of French but I repeat, they are not the same. Cajun is 17th Century French with many of the words trapped in time and many others added by the folks in Southwest Louisiana rather than in Paris.