The earliest Buddhists in India were both men and women, and there were Buddhist nuns as early as Buddhist monks. Some early Buddhist monastic communities had both men and women. This is normal for movements that are just getting started and have a lot of radical members who believe in equality. But after a while, less radical people took over. Then the monasteries were mostly divided, with the women living separately from the men.
In the 400s AD, when people in China first started Buddhist monasteries, there were monasteries for women also. By the 600s AD, there were women’s monasteries in Japan, too. Like the men’s monasteries, these were very successful, and soon thousands of Chinese women became Buddhist nuns. Many women really wanted to spend all their time praying, but other women saw that if they became Buddhist nuns they could get away from being beaten by their fathers or husbands, or they could get better food than they got at home, or they might have more interesting things to do, or be able to travel around China. Also, they would not have to have children if they didn’t want to. Or older women who were widows often joined monasteries, as in Christian Europe. Women (like men) had a lot of different reasons for becoming Buddhist nuns.
Many women entered Buddhist monasteries when they were children, because their parents had promised a child to the monastery in return for some prayer being answered. Inside the monastery, women cleaned and cooked, but they also sang prayer chants and played musical instruments like gongs and bells. Many Buddhist nuns spent most of their day spinning, weaving, or working in the fields, just like other women of their time.