John of Kolno (also known as Jan z Kolna, Johannes Scolnus, Ioannis Scolvenius or Iohannes Scolvus Polonus) (1435–1484)—a semi-legendary Polish sailor and navigator serving for the court of Denmark. According to various sources he was one of the first Europeans to reach the shores of America prior to Columbus in 1476 as steersman of Didrik Pining.

According to Joachim Lelewel (1786 - 1861) the Polish historian and cartographer, who was the first to gather all the available mentions of Johannes Scolnus, the sailor was a navigator of the fleet of Christian I of Denmark. In 1476 he set sail from Norway and led a fleet of several Danish ships westwards. After several weeks he reached the shores of America. The fleet was commanded by two German sailors and pirate hunters Dietrich Pining and Hans Pothorst, who frequently sailed to the shores of Greenland. It is possible that their discovery was made thanks to a navigational mistake or a storm that pushed their ships further westwards.

It is not certain whether John of Kolno really existed and whether he reached America. The first to mention Johannes Scolnus as the discoverer of Labrador (Terra Laboratoris) and the area of present-day Boston was Francisco López de Gómara in his Historia general de las Indias y conquista de Mexico (1552). Other sources to mention Jan z Kolna are:

• Francois de Belleforest 1570
• Cornelius Wytfliet , Descriptionis Ptolemaicae Augmentum 1597 and 1599
• Claude Barthélemy Morisot 1643
• George Horn 1671
• Coronelli 1691
• Charlevoix 1744

There are also mentions of Joannis de Colno who studied at the Kraków Academy in 1455 and the Colno or Cholno family of merchants and sailors living in Gdańsk.

Boleslaw Olszewicz, one of the 20th century historians to criticize the work of Lelewel, argues that there is not enough evidence to prove that the sailor was indeed Polish. Most of the works to mention Johannes Scolnus were published more than a century after his voyage, and there are no contemporary evidence preserved. Also, in the late 19th century various scholars identified John of Kolno as a sailor of Norwegian (Johann Scolv), Portugese (João Scolvo) or German descent.

See also:

• List of Poles
• Pre-Columbian trans-oceanic contact