A man who asked about fasting on Mondays RA

This unnamed man once asked the Prophet ﷺ, as recorded in Sahih Muslim, "Why do you fast on Mondays?" The Prophet ﷺ answered, "This was the day I was born on, and this was the day revelation began to me." The hadith is the certain evidence that the Prophet ﷺ was born on a Monday, though the date of his birth is not agreed upon.