Following the Bulgarian unification and after Ferdinand of the House of Saxe-Coburg and Gotha took over the throne of the Principality of Bulgaria , the country adopted Belgium 's motto of L'union fait la force ( in Bulgarian : Съединението прави силата ) .
After Ferdinand of the House of Saxe-Coburg and Gotha took over the throne of the Principality of Bulgaria , the country started to use Belgium 's motto of L'union fait la force ( in Bulgarian : Съединението прави силата ) .