John Scolvus
John Scolvus or John of Kolno may have been a navigator of the late 15th century. According to some sources he was among a group of early Europeans to reach the shores of the Americas prior to Columbus, arriving in 1476 as steersman of Didrik Pining, although this view is not supported by contemporary evidence; as he is not mentioned contemporaneously, his identity and even existence have been disputed.
It has been claimed that in the 1470s, a fleet of several Danish ships sponsored by Christian I of Denmark set sail from Norway westwards to Greenland. There was such a fleet in 1473 or 1476, commanded by John of Kolno, supposedly a Polish navigator at the service of the king of Denmark. According to speculations lacking surviving written evidence, the fleet was commanded by two Baltic sailors and pirate hunters, Didrik Pining and Hans Pothorst and possibly also included the Portuguese João Vaz Corte-Real on one of the journeys. It has been claimed that from the Western coast of Greenland they may have reached the North American mainland. The story cannot be verified today, since the only surviving records tell us that Pothorst and Pining saw a "rocky island called Hvitsark, halfway between Iceland and Greenland" in 1494, as described by Samuel Eliot Morison in his "The European Discovery of America, The Northern Voyages". John of Kolno by contrast, was a navigator who led a Danish fleet to the coast of Labrador in 1476, or even 1473, according to one source, at the command of Christian I of Denmark.
Speculations
Some historians have variously described Scolvus as a Norwegian pilot, Catalan corsair, Welsh shipmaster and Polish navigator. Such claims have been criticised as being opportunistic in nature. Some writers have even speculated that Johannes Scolvus may have been the young Christopher Columbus, and others that he is identical with Hans Pothorst or João Vaz Corte-Real.
Polish historian and cartographer Joachim Lelewel was the first to gather all available mentions of Johannes Scolnus. He quoted a source from 1570 by François de Belleforest, a source from 1599 by Wytfliet, and another from 1671 which claimed that Scolvus was Polish. Lelewel claimed that his name was really Jan z Kolna, and was the navigator of the Danish fleet. He also found mentions of a Joannis de Colno who studied at the Krakow Academy in 1455, and a Colno or Cholno family of merchants and sailors living in Danzig.
Criticisms
Bolesław Olszewicz, a modern historian who has criticized Lelewel, argues there is not enough evidence to prove that Scolvus was actually Polish. Most of the works that mention Johannes Scolvus were published more than a century after the voyage and no contemporary evidence has been found.