More than one doctor has found their theories dismissed by the existing establishment, only to be proven right years later. Perhaps none of those stories are more dramatic than the story of Werner Forssmann, who, when faced with defeat, simply chose to go around everyone and do his experiment anyway - on himself.
The Reconquista, or Christian reconquest of Iberia, took nearly 800 years. The fighting did not come without great attempts by Muslim powers across the strait trying to reestablish their presence in mainland Europe. The last gasp of that effort came in the 1330s, when the powerful Marinid sultanate of what is modern Morocco invaded in an attempt to reverse Christian gains and secure the perilous position of the Sultanate of Granada.