fp1_apply_generic_stele_bonuses_effect

fp1_apply_generic_stele_bonuses_effect = {
	add_piety = major_piety_gain
	add_prestige = major_prestige_gain
	add_legitimacy = medium_legitimacy_gain
	every_vassal = {
		limit = { fp1_can_raise_stele_trigger = yes }
		custom = fp1_raise_runestone_vassals
		add_opinion = {
			modifier = pleased_opinion
			target = root
			opinion = 10
		}
	}
	# Saga in Stone achievement tracking.
	if = {
		limit = {
			# Grab the player and any dynasty members of theirs.
			any_player = { dynasty = root.dynasty }
		}
		dynasty = {
			# Start a count if we don't have one.
			if = {
				limit = {
					NOT = { exists = var:saga_in_stone_achievement_tally }
				}
				set_variable = {
					name = saga_in_stone_achievement_tally
					value = 1
				}
			}
			# Otherwise, increment it.
			else = {
				change_variable = {
					name = saga_in_stone_achievement_tally
					add = 1
				}
			}
		}
	}
}

As written in game/common/scripted_effects/01_dlc_fp1_scripted_effects.txt.