What is vajk?

Some articles on vajk:

Hunedoara - History
... On October 18, 1409, Vajk (Voicu), a Wallachian (ethnicity is disputed with Vlach, Cuman and Slavic claims), was rewarded for military bravery by ... The same document mentions Mogoş and Radu, brothers of Vajk and John (Ioan), son of Vajk ... Corvinus (Hungarian János Hunyadi Romanian Ioan de Hunedoara), the son of Vajk, spent his childhood here ...
Hunyadi Family
... His son Vojk (alternatively spelled as Voyk or Vajk in English, Voicu in Romanian, Vajk in Hungarian), adopted the name László and practiced Catholicism (a common practice among Romanian cnezes ... Vajk was the second known in the Hunyady family to be a Roman Catholic ...