Lope Díaz de Haro (d. 1322)

As the firstborn son of Diego López V de Haro, Lope Diaz IV was raised believing that he would inherit the Lordship of Biscay.

This led to a lifelong fight between the two parties and a struggle to gain favor with the royal court, both sides having been at times considered at war with the crown.

The agreement also stipulated that the title of lordship over Orduña-Urduña and of Balmaseda, previously associated with Biscay, would remain in Diego Lopez V's immediate bloodline, being transferred to Lope Diaz IV upon his death.

[1] With regards to the accord reached over possession of Biscay, Juan Núñez II de Lara felt under compensated by the king and by his mother reason for which he withdrew from the royal courts in protest without completing his mandate.

In 1310, Diego Lopez V died in camp of wounds received during the siege leaving his possessions with the exception of Biscay to Lope Diaz IV.