The so-called uterus didelphus is really a duplex uterus, or a veritable double uterus, each segment having the appearance of a complete unicorn uterus more or less joined to its neighbor.

Vallisneri relates the history of a woman who was poisoned by cantharides who had two uteruses, one opening into the vagina, the other into the rectum.

Morand, Bartholinus, Tiedemann, Ollivier, Blundell, and many others relate instances of double uterus in which impregnation had occurred, the fetus being retained until the full term.
Purcell of Dublin says that in the summer of 1773 he opened the body of a woman who died in the ninth month of pregnancy.

He found a uterus of ordinary size and form as is usual at this period of gestation, which contained a full-grown fetus, but only one ovary attached to a single Fallopian tube.

On the left side he found a second uterus, unimpregnated and of usual size, to which another ovary and tube were attached.