Philip I, commonly known as Philip of Alsace, was count of Flanders from 1168 to 1191. During his rule Flanders prospered economically. He took part in two crusades and died of disease in the Holy Land.

The count of Flanders was the ruler or sub-ruler of the county of Flanders, beginning in the 9th century. Later, the title would be held for a time, by the rulers of the Holy Roman Empire and Spain. During the French Revolution, in 1790, the county of Flanders was annexed to France and ceased to exist. In the 19th century, the title was appropriated by Belgium and granted twice to younger sons of Belgian kings. The most recent holder died in 1983.