Short answers, pulled from the story.
Sir Humphrey Gilbert (c. 1539-the 9th of September 1583) was an English soldier, explorer, member of parliament, and colonial pioneer who served under Queen Elizabeth I. He was the first Englishman to formally claim Newfoundland for the English Crown, on the 5th of August 1583, and his letters patent formed part of the legal basis for Walter Raleigh's later Roanoke expeditions.
Gilbert drowned on the 9th of September 1583 when his small frigate Squirrell sank in a storm near the Azores, roughly nine hundred miles from Cape Race. He had refused to transfer to the larger Golden Hind despite warnings the Squirrell was over-gunned and unsafe; the last the crew of the Golden Hind heard from him was the repeated cry, "We are as near to Heaven by sea as by land!"
Humphrey Gilbert was a maternal half-brother of Sir Walter Raleigh. Both men were sons of Catherine Champernowne; Raleigh and his brother Carew were her children by a later marriage. Raleigh commanded the Falcon on Gilbert's 1578 expedition and owned the Bark Raleigh, which was part of Gilbert's 1583 fleet before turning back for lack of supplies.
Gilbert served in Ireland between 1566 and 1572 under Sir Henry Sidney, fighting during the Tudor conquest of Ireland. He was appointed governor of Ulster after Shane O'Neill's assassination in 1567, and in 1569 he was promoted to colonel and led a brutal campaign against the Geraldines of Desmond, during which he ordered the heads of those killed to be displayed along the path to his tent as a terror tactic.
During the winter of 1566, Gilbert argued before Queen Elizabeth that a northeast passage to China was too dangerous because near the pole the air was "so darkened with continual mists and fogs" that no navigator could steer. He contended that a northwest passage by way of America was the viable route. His argument helped secure funding for Martin Frobisher's 1576 expedition, though Frobisher found no passage.
Gilbert claimed Newfoundland for the English Crown on the 5th of August 1583 at the port of St. John's. The ceremony followed common law practice: turf was cut from the ground to symbolize transfer of the soil. He also claimed authority over all lands two hundred leagues north and south of Newfoundland and levied taxes on the fishermen of several nations working the Grand Banks.