If you are during combat, or siege , you must pay a ransom (in combat or duel the alternative is death, at tourneys you can welch, but then the guy you stiffed can challenge you to a duel to the death). Ransoms are fixed as a percentage of your GDP at the time of capture. This concept is called "auto-ransom." If you pay right away, you are automatically released the next season. If you wait, the amount of ransom goes down each season for ten seasons until it levels off. You can't travel, or do much of anything else except manage your fiefs while a prisoner. You can attend the IC. Kings are not eligible for auto-ransom. Their ransom must be negotiated. Any other player may also negotiate a ransom.