By God Alone achievement

Servus Servorum Dei

Starting as a Duke-or-lower secular ruler, or a Count-tier cleric, become the Pope

Conditions as the game checks them

Possible decides whether the achievement can still be earned in a run; happened is the check that unlocks it (common/achievements/_achievements.info).

Unlocks when (happened) (6 lines of game script)

custom_description = {
	text = ce3_11_servus_servorum_dei_achievement_trigger
	has_character_flag = ce3_11_servus_servorum_dei_achievement_start
	has_title = title:k_papal_state
	pam_pope_is_head_of_faith_or_rite_trigger = yes
}

As written in game/common/achievements/ce3_achievements.txt.

Still possible while (possible) (1 line of game script)

has_character_flag = ce3_11_servus_servorum_dei_achievement_start

As written in game/common/achievements/ce3_achievements.txt.

Source: game/common/achievements/ce3_achievements.txt, game/common/achievement_groups.txt and the English localisation, Crusader Kings III 1.20.0.3.