Arnau Mir de Tost and the Àger valley Historical milestone · Àger, Noguera, Lleida Image of Àger, not of the place itself. A nobleman and soldier of the county of Urgell born shortly after the year 1000, Arnau Mir de Tost, of the House of Tost in Alt Urgell, bought Llordà castle together with his wife Arsenda and from there extended his domains southward, conquering the Àger valley from the Muslims in 1048 — who had earlier retaken it — and was made lord of Àger. There he built a fortress and the collegiate church of Sant Pere, whose independence from the bishops, especially that of Urgell, and the right to appoint its own abbot, he obtained from Pope Nicholas II thanks to Arsenda's efforts. He came to hold more than thirty castles between the Solsonès and the Montsec. He died in 1072 without a male heir, and the viscounty of Àger passed to his daughter Letgarda. siglo XI Photo: jordi domènech (CC BY-SA 3.0) What to see and do in Àger