In 1430, led by chieftain Edzard Cirksena of Greetsiel, a freedom-alliance was formed against the ruling Focko Ukena.

After the marriage in 1455 of Ulrich Cirksena with Theda Ukena, a granddaughter of his enemy, the majority of East Frisia was united.

Sibet Attena, a nephew and aid to Ulrich received the Lordships of Esens, Stedesdorf and Wittmund, which together formed the historic region of Harlingerland.

Because Ocko I tom Brok had given the territory to the count of Holland in 1381, the status of the rulers of East Frisia was unclear.

The ruler of East Frisia decided to improve his situation by turning directly to the Holy Roman Emperor.

The emperor gave to Ulrich I the Imperial County in Norden, Emden, Emisgonien in East Frisia.

Theda managed to withstand the threats of Duke Charles the Bold of Burgundy and count Gerd of Oldenburg.

A new situation was created with the appointment of George of Saxony as imperial stadtholder of Friesland by Maximilian I, Holy Roman Emperor.

After 1519 the Protestant Reformation made its way into East Frisia, initially with a very tolerant view towards Roman Catholicism.

The city of Emden became a popular destination for Dutch Calvinists fleeing from religious persecution in the Netherlands.

In 1602, count Enno attempted to drive out the Dutch with support from the Emperor and the Spanish king, but he was rebuffed.