How was India discovered in Medieval Europe?

The medieval Europeans knew India from ancient reports. India had commercial exchanges with the Greeks and probably before them, also with Egypt and the Middle East empires. The first known European in set a foot in Indian soil was Alexander the Great with his army in the IV-th century BC He fought against the king Phoro in the outskirts of the Indo river, becoming later allies. This is the most distant point that Alexander reached. Furthermore he charged his admiral Nearcho to navigate the Indo river.

The Europeans "rediscovered" the India (maybe we must say returned to India) in the XV th Century with the Portuguese explorer Vasco da Gama's voyage. He sailed around Africa and reached the city of Goa.

Odoric of Pordenone (real name Odoric Mattiussi or Mattiuzzi) (c. 1286 -- 14 January 1331), was known to have visited India in around 1321 or 1322