Not every great man is a great human being.

[Nicht jeder große Mann is ein großer Mensch.]

Marie von Ebner-Eschenbach (1830-1916) Austrian writer

Aphorisms [Aphorismen], No. 267 (1880) [tr. Scrase/Mieder (1994)]
    (Source)

(Source (German)). Alternate translation:

Not every great man is a grand human being.
[tr. Wister (1883)]