Grady McWhiney Grady McWhiney ( July 15 , 1928 – April 18 , 2006 ) was a historian of the American south and the Civil War . McWhiney was born in Shreveport , Louisiana , and served in the Marine Corps in 1945 . He married in 1947 . He attended Centenary College on the G . I . Bill and earned an Master of Arts in history from Louisiana State University , working with Francis Butler Simkins . He received his Ph . D . in history from Columbia University in New York , working with David Herbert Donald . McWhiney ' s dissertation dealt with Confederate General Braxton Bragg . McWhiney became a noted specialist on the American Civil War era , as well as southern social and economic history . He coauthored " Attack and Die " with his doctoral student Perry Jamieson . He published " Braxton Bragg and Confederate Defeat " , in two volumes , as well as many scholarly and popular articles and reviews . He lectured frequently to both academic and popular audiences . McWhiney and Forrest McDonald were the authors of the " Celtic Thesis , " which holds that most Southerners were of Celtic ancestry ( as opposed to Anglo - Saxon ) , and that all groups he declared to be " Celtic " ( Scots - Irish , Irish , Scottish , Welsh and Cornish ) were descended from warlike herdsmen , in contrast to the peaceful farmers who predominated in England . They attempted to trace numerous ways in which the Celtic culture shaped social , economic and military behavior . For example , they demonstrated that livestock raising ( especially of cattle and hogs ) developed a more individualistic , militant society than tilling the soil . " Attack and Die " stressed the ferocity of the Celtic warrior tradition . In " Continuity in Celtic Warfare . " ( 1981 ) McWhiney argues that an analysis of Celtic warfare from 225 BC to 1865 demonstrates cultural continuity . The Celts repeatedly took high risks that resulted in lost battles and lost wars . Celts were not self - disciplined , patient , or tenacious . They fought boldly but recklessly in the battles of Telamon ( 225 BC ) , Culloden ( 1746 ) and Gettysburg ( 1863 ) . According to their thesis , the South lost the Civil War because Southerners fought like their Celtic ancestors , who were intensely loyal to their leaders but lacked efficiency , perseverance , and foresight . In 1993 he argued the fundamental differences between North and South developed during the 18th century , when Celtic migrants first settled in the Old South . Some of the fundamental attributes that caused the Old South to adopt anti - English values and practices were Celtic social organization , language , and means of livelihood . It was supposedly the Celtic values and traditions that set the agrarian South apart from the industrialized civilization developing in the North . However , McWhiney ' s theories do not address large - scale Irish immigration to New York , Boston , and other northern cities . They also ignore the degree to which the Southern planter class resembled the English gentry in lineage , religion , and social structure . Furthermore his work avoids mentioning or acknowledging the fact that the largest group of pre - Revolution immigrants to the Southern colonies were English indentured servants who vastly outnumbered the " Celtic " settlers both in numbers and in cultural influence . , McWhiney taught at numerous institutions including Troy State University , Millsaps College , the University of California , Berkeley , Northwestern University , the University of British Columbia , Wayne State University , the University of Alabama , Texas Christian University , The University of Southern Mississippi , and McMurry University . Over a 44 - year career , he trained 19 history Ph . Ds . Grady McWhiney was deeply concerned about the future of history in the schools , explaining , “ history should be accessible . ” He founded the Grady McWhiney Research Foundation , located in Abilene , Texas . McWhiney was a former director of the League of the South , but he had broken with the group prior to his death . As historian C . David Dalton has pointed out , he was " Controversial . Unconventional . Influential . These are words easily applied to one of the South ' s most prominent scholars , Grady McWhiney . For over three decades his writings have been discussed and debated but never disregarded . "