1. Confusion of different Eumolpus of the era
 Apollodorus, Greek author of 2nd-century AD,  says “Chione had borne Eumolpus, and Eumolpus went with his son Ismarus to  Tegyrius, king of Thrace. In  addition, she fled from Thrace to the Eleusis, and after the death of Ismarus,  Eumolpus was greeted by Thrace and became the successor to Tegyrius. When  Athenae and the Eleusis people fought, Eumolpus led the army from Thrace and  helped the Eleusis. In this fight Eumolpus was  killed by Erechtheus, but Erechtheus also died.”. (1) 
      This Eumolpus’s mother Chione was the daughter of Orithyia.  (2) And the father of Orithyia was the 6th Athenian  King. (3)  If Apollodorus’s account is accurate,  Eumolpus was the great-grandson of Erechtheus. But when I looked at the genealogy, it  seems that Erechtheus (Born BC 1430) had already  died before Eumolpus (Born BC 1330) was born.
      Thukydides, Greek historian of  5th- century BC, and Hyginus, ancient Roman  authorship of 1st- century  BC, and Apollodorus says “Eumolpus and Erechtheus fought.”.  The army commanded by  Eumolpus was Eleusis in Thukydides and Thrace in Apollodorus but unknown in  Hyginus. Hyginus and Apollodorus says that both are dead, but are  unknown in Thukydides. 
      2 Eonolpus of the same generation as Ion and Erechtheus
         Eumolpus after the description of Apollodorus was the leader of the Thrace. He invaded Attica in BC1420 when the 5th Athenian King Pandion died  and the 6th athenian King Erechtheus was childhood,  and h settled in Eleusis on the west side from Rheiti river. (4) 
        He fought with  the Athenians, the Athenians elected Xuthus’s Ion(Born BC  1430) as commander, promoted fighting advantageously with Eumolpus, brought it  to armistice. (5) Dysaules, the same family as Eumolpus, were  expelled from Eleusis by Ion, but Eumolpus remained in Eleusis. (6) 
        Became the  generation of Immaradus son of Eumolpus, again fighting with the 6th Athenian  King Erechtheus, both of them died. (7)  After  that Eumolpus performed a divine work with the daughters of Celeus. (8) 
        This Eumolpus is presumed to be born in BC1450. 
      3 Eonolpus of the same generation as Hercules
         Eumolpus before  the description of Apollodorus, the great-grandfather was the Athenian  Erechtheus, but the grandfather was the Thrace Boreas.  (9) It is said that Eumolpus cleansed Hercules  and joined them quietly. (10) 
This Eumolpus is presumed  to be born in BC1330.