This needs a drone! But there is nothing medieval about this piece. It was written in the melodic minor scale, but the typical upward motion does not appear in the melody. However, perhaps this could be a clue for your own parts and improvisations.
%%printTempo 0 X:1 M:2/2 L:1/8 Q:1/2=75 K:Am |: e4 dcBc | A6 A1/2B1/2c1/2d1/2 | e2 e2 A2 a2 | g3 f e4 | e4 dcBA | B6 cd | e2 a2 e2 Bc | decB A4 :| |: B3 c d3 e | f3 a g3 f | e2 de B4 | edec B4 | B2 Bc d2 de | f2 fa g2 f2 | e2 AB c3 d | B2 Bd f2 d2 || e4 dcBc | A6 A1/2B1/2c1/2d1/2 | e2 e2 A2 a2 | g3 f e4 | e4 dcBA | B6 cd | eAAd c4 | BddB A4 :|]