Around the year 1010 — the earliest documented Eucharistic miracle of Spain — Father Bernat Oliver, parish priest of the small Catalan village of Ivorra and tormented by doubts about the Real Presence, was celebrating Mass when, at the moment of consecration, the wine in his chalice boiled, overflowed, and visibly turned to blood.
Pope Sergius IV, alerted by the bishop of Vic and provided with the bloodied corporal, formally approved the cult by a 1011 bull (Litteris vestris) — one of the earliest papal approvals of a Eucharistic miracle. The Sanctuary of Santuari del Sant Dubte ('Holy Doubt') in Ivorra preserves the relic.