For centuries ethnic Danes and Germans lived together peacefully in the independent Duchy of Schleswig. In 1864, Schleswig's independence ended when it was formally incorporated into Prussia, a predominantly German-speaking nation. This also resulted in the creation of a large Danish minority in northern Schleswig. A final border revision in 1920 repatriated most ethnic Danes, but it also established a German minority in Denmark. Since then, both Denmark and Germany have provided robust cultural and educational programming and services, including libraries, to help preserve connections for ethnic Danes and Germans to their ancestral homeland. This paper provides an overview of Schleswig's history prior to and immediately following the 1920 border revision. Its main focus, however, is on the comprehensive public library services provided to Schleswig's ethnic Danes and Germans. The libraries are unique, and they play a vital role in educating Schleswig's ethnic Danes and Germans about their ancestral homelands, while promoting civic engagement in their adopted countries. [ABSTRACT FROM AUTHOR]