Vagrant Story and FFXII both are directed by Yasumi Matsuno
if you now know him. he's the guy that make Final Fantasy Tactics
he leave some trail in his game that the player can feel that item's name, place or something that combine in same realm but in other game, other time
example: Vagrant Story is set in Valendia. Valendia is one of the continents in Final Fantasy XII but you will not see Ashley or any character from Vagrant Story in FFXII
this is one of many reason that's why Vagrant Story and Final Fantasy XII got full score from famitsu
to know everything about relation between this two game
http://finalfantasy.wikia.com/wiki/Vagrant_Story
this site have great information that you will never know before