Cathedral Window from about 1970
Franklin, Indiana Journal
1965
We can guess what Mrs. Stainbrook's Cathedral Window quilt looked like in 1965 as the pattern fad included unwritten rules.
By 1981 the rules hadn't changed much.
1) The windows were scraps of various colors with no set pattern of dark light, etc.
2) The background was white (or that ever popular mid-20th-century unbleached muslin).
The "quilt" was not quilted; a three-dimensional folding technique resulted in squares that were layered and stitched into an intricate all over design.
Amanda Farquarson's how-to
The intricacy was kind of fascinating---but time consuming.
Leslie started this one when she was 11 in
the 1980s and finished it in 2004.
Dorothy Loman told the Michigan Project she made
this unusual shaded version in 1984.
A search through the Quilt Index finds 268 examples.
Two colors! One might miss the fun of examining each print as one folds and stitches.
We can see this as a mid-20th-century fashion but what's the earliest reference to a Cathedral Window quilt? A search of newspapers finds a flurry in North Carolina.
November 1961, Burlington, North Carolina
October, 1962
Burlington, North Carolina
About a year later, Nina Patterson taught a workshop. The E.M. Holt
club might have been a teaching arm of the local EHU agency. (Holt
had established mills in Alamance County.) EHU =
Extension Homemaker Units 
The EHU's were probably behind many quilt trends of the 20th century. They taught home economics: food preparation, sewing and housekeeping to farmers and their families throughout the U.S.
1965 Charlotte, North Carolina News
The earliest published pattern for the technique was called
Mock Orange in Workbasket magazine in August, 1944.
The center window was pieced.
Note the fabric requirements: "22-1/2 yards of white...."
Can't imagine why this didn't catch on during the fabric shortages
of World War II.
Attic Window from the Laura Wheeler/
Alice Brooks syndicate, published in October, 1969 and into the 1970s.
Albertine Ziehl told the Michigan project she found
her pattern in Woman's Day magazine. Note two sizes of blocks.
Bet she started out with the smaller squares and then....
I confess I began one of these with much ambition in the 1970s---made 25 squares,
wound up as a small pillow. As I recall the scraps were browns like the one
above. Another fad at the time.
Frances Treder of Benton Harbor, Michigan,
was more persistent and finished hers in 1967.
Above: One reason for pattern popularity: "The nice thing about this is it doesn't have to be quilted."
In the 1960s people were looking for ways to get around that step---"Quilt As You Go" in several variations.
You can buy this one on Etsy.
What can we learn from all this? When dating Cathedral Windows look at the prints, but consider the early 1960s as the fad's beginning. And do recall that Workbasket published it as early as 1944. Someone may have had 22 yards of white fabric at hand.