Who would have guessed that there is a genre out there called nunsploitation. I am not sure what it means, but this film appears to be included.
It is the story of a Mexican nun that was decidedly feminist. You can look up Juana Inés de la Cruz on Wikipedia and it will give you more. Apparently this film is historically accurate according to those I have consulted.
The main thrust of this film is the intense hatred (Can one say fear?) of women by the Church through the ages, which continues to this day. It examines the Inquisition, by which the Church sought to stifle creativity and thinking.
One would do well to know the status of women in the Church at the time to properly understand and enjoy this film. The role of women can be defined: "it is right for (women) to pride themselves on being silent, both those for whom it is convenient to cover up their lack of knowledge, and those who might shamelessly reveal what they know, because in all of them it is not only an agreeable condition, but a proper virtue, to speak little and be silent." Unlike Saint Teresa, Sr Juana is castigated not canonized for the audacity to speak her mind, to seek knowledge, and to think.
If you seek the "lesbian passion behind convent walls" that is on the DVD cover, you will be sorely disappointed. While a lesbian relationship might be strongly suggested between Sr Juana and her noble protectress, it is never overtly expressed with the exception of a kiss that would be considered an "air kiss" compared to the one Phoebe gave Rachel on "Friends." The film was extremely interesting and Assumpta Serna was outstanding as Sr Juana.