According to Merriam-Webster's Collegiate Dictionary, Tenth Edition (www.m-w.com), autarchy means absolute sovereignty, not self-sufficiency as Webster 1913 claims. When the usage of this word has changed I'm not sure but according to Merriam-Webster Autarchy has been in use since 1665. According to my two sources the word which Webster 1913 could be thinking of is autarky.