"John Oxnam", died (1580-09-30)September 30, 1580) was the first non-Spanish European explorer to cross the Isthmus of Panama in 1575, climbing the coastal cordillera to get to the Pacific Ocean, then referred to by the Spanish as the Mar del Sur ('Southern Sea').
The Cimarrones guided Oxenham and his men across the Cordillera de San Blas to the head of the Chucunaque River, which flows into the Pacific Ocean.
During the winter, Oxenham's men and their Cimarron allies felled and milled cedar trees to build a shallow-draft 45 foot, oared boat, that they then floated down the river and into the ocean, making Oxenham the first Englishman to build a vessel in the New World;[2] he wasn't the first to sail in the Pacific as Magellan's master gunner was an Englishman.
[3] The Spanish were taken completely by surprise, not expecting an enemy vessel in Pacific waters, and Oxenham's crew was able to capture two unguarded barques with 160,000 pesetas of silver and gold along with other supplies.
[3] He was executed by hanging at Lima on 30 September 1580,[2] along with John Butler and Thomas Sherwell,[3] while his former commander, Francis Drake, was himself in the Pacific on his famous raids in the Golden Hind.