Context : Andrzej Jastrzębiec, also known as Andrzej Wasilko or Andrzej Polak, (died 1398) was a Polish Catholic priest and diplomat, a first bishop of Seret and of Vilnius. 
Subject : Andrzej Jastrzębiec 
Relation : date of death
On what date did Andrzej Jastrzębiec die?