Which group of people did the 14th amendment grant citizenship to ?

Granted citizenship to all person "who is born or naturalized in the United States" which includes formers slaves recently freed

The league of nations was found in 1919 to keep peace after world war l.but it failed to prevent world war ll in 1939,so in 1945 the nations of the world set up a new organization,the united state (un).since then, the un has encouraged international cooperation and worked to resolve conflict