290398
Hero Oomkens von Esens ' marriage to Armgard Countess of Oldenburg in 1489 helped to cement the alliance of the old Frisian aristocracy with the Counts of Oldenburg in their struggle against the rise of the Cirksena family .
 Hero Oomkens von Esens, Oldenburg, Oldenburg
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Hero Oomkens von Esens, Oldenburg, Oldenburg