Official rule text
61.1 There are two types of objective cards: public objectives and objective’s card. Then, that player advances secret objectives. their control token on the victory point track a number of spaces equal to the number of a Each public objective has a “I” or “II” on the back of its victory points gained. card; all other objectives are secret objectives.
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Source: Twilight Imperium: Fourth Edition - Living Rules Reference: Prophecy of Kings
Expansion: Prophecy of Kings
Version: 2.0
Reference: Rule 61.1