Margaret I of Flanders

Margaret I of Alsace (died November 15 1194) was countess of Flanders from 1191 to her death. She was the daughter of Thierry, Count of Flanders, and Sibylle of Anjou, and the heiress of her childless brother, Philip of Flanders.

In 1169 she married Baldwin V, Count of Hainaut, who became her co-ruler.