The three veils of darkness

"He makes you in the wombs of your mothers in stages, one after another, in three veils of darkness." (Quran 36:6)

This statement is from Sura 39:6. We do not know when it was realized that human beings underwent development in the uterus (womb), but the first known illustration of a fetus in the uterus was drawn by Leonardo da Vinci in the 15th century. In the 2nd century A.D., Galen escribed the placenta and fetal membranes in his book "On The Formation of the Foetus."

Consequently, doctors in the 7th century A.D. likely knew that the human embryo developed in the uterus. It is unlikely that they knew that it developed in stages, even though Aristotle had described the stages of development of the chick embryo in the 4th century B.C.

The realization that the human embryo develops in stages was not discussed and illustrated until the 15th century.

After the microscope was discovered in the 17th century by Leeuwenhoek descriptions were made of the early stages of the chick embryo. The staging of human embryos was not described until the 20th century. Streeter (1941) developed the first system of staging which has now been replaced by a more accurate system proposed by O'Rahilly (1972).

"The three veils of darkness" may refer to:

(1) the anterior abdominal wall;
(2) the uterine wall;
and (3) the amniochorionic membrane .

Although there are other interpretations of this statement, the one presented here seems the most logical from an embryological point of view.