The first count of Holland, Dirk I, was the son or foster-son of Gerolf, Count in Frisia (Dijkstra suggests that Dirk may have been the son of a sister of Gerolf and that his own father died while he was still an infant). He received land around Egmond from Charles the Fat at a place called Bladella (modern day Bladel near Eindhoven, The Netherlands) in 922. This is seen as the beginning of the county of Holland. However, until about 1100, the usual names for the county were West-Friesland, Frisia or Kennemerland; in spite of this the counts from Dirk I onwards are traditionally named of Holland.
Note that the chronology of the first few counts is uncertain. The existence of a count between Dirk I and Dirk II was only recently suggested, since it is thought that the references to counts named Dirk between 896 and 988 refer to three, not two, different counts. This third Count Dirk is placed between Dirk I and II and numbered as Dirk I bis to avoid confusion with the already established numbering referring to the other counts of Holland named Dirk.
During the rule of Margaret, her son William V had the real power in the county. He became ruler in his own right as a result of the Hook and Cod wars. He was also Duke of Bavaria-Straubing as William I.
There was a war of succession between John III and Jacqueline. This war was finally won by Philip of Burgundy in 1432, who, in the meantime had inherited John's claims on the county. Philip was a nephew of William VI, who had married a daughter of Philip the Bold of Burgundy. In 1432 he forced Jacqueline to abdicate from Hainaut and Holland on his behalf.
During the 'foreign rule' by Burgundy and Habsburg, the county was governed by a stadtholder in name of the count. In 1581, the Estates General of the United Provinces declared themselves independent from the Spanish rule of Philip II (who was Philip III of Holland). Until the Treaty of Münster in 1648, the kings of Spain still used the title Count of Holland, but they had lost the actual power over the county to the States of Holland.
The county remained in existence as a constituent member state of the Dutch Republic until 1795. There were no more counts however since the Estates of Holland and West-Frisia were the sovereign of the county (although the countship was offered to William the Silent in 1584, shortly before his death). The stadtholders, who were servants of the Estates, were the de facto chief-executives during this period.