Abiathar was one of two chief priests in the court of King David, about 3000 years ago in Israel.
Abiathar was the son of Ahimelech of the priestly clan of Eli from Shiloh (1 Samuel 22:20). When the residents of the priestly village of Nob were massacred by King Saul for helping David, Abiathar was the only one to escape.
When David eventually became king, he appointed Abiathar, along with Zardok, as priests of the royal court (2 Samuel 8:17).
Abiathar and Zardok carried the Ark of the Covenant out of the capitol city, when David was forced to leave Jerusalem, because of Absalom's rebellion - but later returned it.
Both priests remained in Jerusalem to inform David of Absalom's plans (2 Samuel 15:34). After Absalom's death, Abiathar and Zardok carried the message of reconciliation to Amasa and the elders of Judah. (2 Samuel 19:11-14).
During the struggle over who would succeed David as king, Abiathar supported Adonijah. When Solomon emerged as the new ruler, Zardok was appointed priest of the royal court, while Abiathar escaped execution only because of his earlier loyalty to David.
Abiathar and his family were banished to Anathoth, and his rights and privileges as a Jerusalem priest were taken away (1 Kings 1:7-25; 1 Kings 2:22-35).
The name Abiathar means "father of abundance."