As indicated by the caption, this image shows a German knight's Maximilian Armor, made in 1525 and seen at the left in the south passageway photograph here in the Library.
The caption accompanying this image reads as follows:
A German knight's Maximilian Armor, made in 1525 and seen at the feft, in the passageway photograph above.
Obviously, the word "feft" in the caption should have been "left" instead.
See Harbor Hill, Clarence Hungerford Mackay's Mansion.
