What is the ruling on separating men and women in the mosque by placing a wall or curtain, and is it preferable for them to pray together, and when did this separation begin?

Separating men and women with a barrier is a good practice that aligns with the objectives of Sharia (definition) in reducing intermingling. Similar precautions have been reported in the Sunnah (definition), including: making the best rows for women the last ones, due to their distance from men; dedicating a door in the mosque for women; and the Prophet, peace and blessings be upon him, remaining in place after the salutation so that women could leave first. These texts indicate the permissibility of taking any precaution that prevents or reduces intermingling, provided it does not affect women's ability to follow the Imam. Determining the exact time when this separation began is not of great benefit; what is important is understanding the Sharia ruling.