Sir Walter Raleigh before the judges in 1618. Previously tried for treason in 1603, Raleigh was released in 1616, in order to conduct a second expedition to Venezuela in search of El Dorado, during which he attacked the Spanish outpost of Santo Tom? de Guayanaon. The Spanish ambassador successfully demanded that King James reinstate Raleigh's death sentence and on his return he was once more arrested. Sir Walter Raleigh, c. 1554 1618. English aristocrat, writer, poet, soldier, politician, courtier, spy, and explorer. From The Century Edition of Cassell's History of England, published 1901.