He pursued a military career, serving in Europe before joining Pánfilo de Narváez in an expedition to Florida in 1527. When it failed, he and three other survivors spent ten years trekking 6000 miles through the south of North America and back to New Spain. He hoped to command another expedition, but delays in returning to Spain lost him the opportunity. Instead he was made governor of Rio de La Plata, and led two 1000-mile expeditions through the jungles and up the Rio Paraguay in 1541 and 1542. Arrested in 1543 by jealous colleagues, whom he had prohibited from looting and enslaving the local Indians, he was returned to Spain in chains. His sentence of eight years’ exile in Africa was annulled, however, and a royal pension enabled him to write his Commentarios on his South American treks.