As I understand, the name of the kingdom/country of England is derived from the Germanic tribe of the Angles who migrated there during the Migration Period. At the same time as the Angles were arriving in Britain, however, other Germanic tribes were also settling in Britain, including the Jutes and, most notably, the Saxons. It seems that the Saxons made a much larger splash than the Angles or Jutes though, lending their names to kingdoms and place names such as Wessex, Sussex, Essex, etc. Further most historical (or at least pop-history) references to the post-Roman rulers of south and east Britain refer to either the Anglo-Saxons or, more commonly, simply the Saxons. Even before the collapse of the Western Roman Empire, the Saxons seem far more notable than the other Britain-bound tribes (as seen in a defense system being named the "Saxon Shore").

And yet, England remains England - Angle-Land. Why? Why did the Jutes leave their name behind in Denmark (Jutland, I assume, is named after the Jutes), and the Saxons bring their name with them when they migrated east (to modern Saxony)? Why did the Anglo-Saxons refer to themselves as Engles, making Æthalstan the King of the English?