private function formatDates(array $gedcom_dates): array
    {
        $dates = [];

        foreach ($gedcom_dates as $gedcom_date) {
            // PHP converts numeric array keys ('1900') to integers (1900), so reverse this.
            $gedcom_date = (string) $gedcom_date;

            $date                = new Date($gedcom_date);
            $dates[$gedcom_date] = strip_tags($date->display(false, null, false));
        }

        return $dates;
    }