Arnau Mir de Tost

Arnau Mir de Tost[1] (c. 1000 – after 1072) was a Catalan nobleman of Urgell, the lord of Llordà and viscount of Àger, a major figure in the eleventh-century Reconquista in Catalonia.

Arnau is sometimes praised as the "El Cid of the Lands of Lleida" for his foundational role in reestablishing Christian rule in the region to the south of Urgell.

[3] His crowning achievement was to seize the mighty qaṣabah (Arabic: قصبة) of Ajīra (Àger) in 1034, the key fortress in the Andalusi line of defence (the Tagr) against Urgell, which he successfully took by storm twice.

[5] Arnau had extended his influence into Pallars Jussà through this matrimonial alliance (1055), at which time Raymond had pledged him four castles as insurance against his breaking his marriage vows.

[6] Arnau controlled over thirty castles and numerous other agricultural settlements at the height of his power, justifying his assumption of the titles of viscount[4] and comtor.