I've seen this claim repeatedly:
The lives of the people who responded to the Quran have changed drastically. It had a tremendous impact on so many people, especially women, since this was the first time that the souls of man and women were declared equal -- with the same obligations as well as the same rewards. -- IslamWeb
In a world where women were no more than objects of sexual gratification for men, and at a time when the religious circles argued over whether women were human or not, possessing souls, Islam proclaimed: “O mankind! We created you from a single (pair) of a male and a female.” [Al-Qur’an 49:13] -- WhyIslam.org (pdf)
(And it's probably related to how a claim by Alan Turing arose: Do women have soul according to Islam or its various sects?)
Question: Was whether or not women have souls in debate prior to Islam?
I'm after concrete evidence that this claim is true (if it is true).