steal_artifact_in_event_effect

steal_artifact_in_event_effect = {
	if = {
		limit = { exists = $VICTIM$.capital_province }
		set_local_variable = {
			name = location
			value = $VICTIM$.capital_province
		}
	}
	else_if = {
		limit = { exists = $VICTIM$.location }
		set_local_variable = {
			name = location
			value = $VICTIM$.location
		}
	}

	$ARTIFACT$ = {
		save_scope_as = artifact_to_steal
		hidden_effect = {
			if = {
				limit = {
					exists = local_var:location
				}
				set_owner = {
					target = $THIEF$
					history = {
						type = stolen
						actor = $VICTIM$ #stolen from
						recipient = $THIEF$ #stealer
						location = local_var:location
					}
				}
			}
			else = { #If no location exists it is "conquered"
				set_owner = {
					target = $THIEF$
					history = {
						type = conquest
						actor = $THIEF$ #stealer
						recipient = $VICTIM$ #stolen from
					}
				}
			}
			if = {
				limit = {
					NOT = { has_variable = stolen_artifact }
				}
				set_variable = {
					name = stolen_artifact
					value = 1
				}
			}
			else = {
				change_variable = {
					name = stolen_artifact
					add = 1
				}
			}
		}
	}
	$VICTIM$ = {
		add_personal_artifact_claim = scope:artifact_to_steal
	}
}

As written in game/common/scripted_effects/00_ep1_artifact_effects.txt.