JIDDA, Saudi Arabia — What if, for 40 years, government-run schools and mosques taught the same refrain — that women’s brains were smaller than men’s and couldn’t process complex information, that it was shameful for women to interact publicly with strangers, that sitting behind the wheel of a car could cause birth defects for a pregnant woman’s child?

And then, what if the government suddenly reversed itself?

The Saudi ruler announced nine months ago that he would grant women the legal right to drive. But many Saudis were still trying to process their new reality on Sunday, the first day that overturned what had been one of the most sacrosanct prohibitions in the absolute monarchy.

It’s unclear just how many Saudi women took to the streets to celebrate their new freedoms. The government announced that hundreds of women would have their licenses by Sunday. Bureaucratic delays have kept tens of thousands more from getting their permits in time for the historic day.