Complex sentence: The monument represents "The Nation at Peace Won Through Victorious War"; and was finished in 1911 by American Sculptor Hermon A. MacNeil and erected in 1912 by the GAR as a monument to Civil War veterans.
Split into simpler sentences: The monument represents "The Nation at Peace Won Through Victorious War". It was finished in 1911 by American Sculptor Hermon A. MacNeil and erected in 1912 by the Grand Army of the Republic as a monument to Civil War veterans.