Ermengol or Armengol IV (1056–1092), called el de Gerb or Gerp, was the count of Urgell from 1066 to his death.
[a][b] Ermengol inherited Urgell when he was only ten years old and ruled under the tutelage of the countess dowager, Sancha, third wife of his father, until he was twelve.
In 1076, having brought the nobles to submission, he began a Reconquista of his own, taking the basin of the river Sió with the villages of Agramunt and Almenar that year and Linyola and Belcaire in 1091.
He conquered Calassanç and built a castle at Gerb, Spain, where he later died, in an effort to pave the way to the recapture of Balaguer, which occurred during the reign of his son, Ermengol V, in 1102.
In 1077, Ermengol married Lucy, daughter of Artau I, Count of Pallars Sobirà,[3] and granddaughter of Bernard I of La Marche.