Official rule text
98.7 The game ends immediately when one player has 10 victory points. If multiple players would simultaneously gain their 10th victory point, the player who is earliest in initiative order among those players is the winner; if this occurs when players do not have strategy cards, the player who is nearest the speaker (including the speaker) in clockwise order is the winner.
View official source
Source: Living Rules Reference and FAQ - Prophecy of Kings
Expansion: Prophecy of Kings
Version: 2.0
Reference: Rule 98.7