
Window in the Peacock Room dates from about 1884.

Window in the Peacock Room, I. S. Gardner Museum
It is catalogued in MacDonald 1995 (cat. rais.) [more] (cat. no. 990).

Window in the Peacock Room, I. S. Gardner Museum

N.E. corner of the Peacock Room, Freer Gallery of Art

Shutters in the Peacock Room, Freer Gallery of Art

Window in the Peacock Room, I. S. Gardner Museum

N.E. corner of the Peacock Room, Freer Gallery of Art
A memory drawing of the windows of Harmony in Blue and Gold: The Peacock Room y178, the house of Frederick Richards Leyland (1832-1892) in Princes Gate, London.

Window in the Peacock Room, I. S. Gardner Museum

Shutters in the Peacock Room, Freer Gallery of Art
This is a memory drawing, the only one that shows the windows, rather than the closed shutters. It is not a preliminary study for Harmony in Blue and Gold: The Peacock Room y178.
Hadley considered the drawings were made in preparation for the decoration, but this is unlikely. 1
It was not, as far as is known, exhibited in Whistler's lifetime.
1: Hadley 1968 [more], pp. 37-41, no. 18.