Also to be found on the other Voynich Wiki here [1]

Originally Jiří Bareš, Also known as Georgius Barschius. He was born in 1585, and received his baccalaureate in 1602, and was a Czech antique collector from Prague. He died in 1662.

Medieval European alchemist and antique collector from Prague, and the earliest confirmed owner of the Voynich Manuscript, about which he was in correspondence with Athanasius Kircher in the late 1630s, having already owned the Manuscript for some time.

More information on the Wikipedia page [2] and the Voynich Manuscript Biographies page [3]: a mention here [4]. Details of the letters can be found here [5]. Wikidata page [6].