Under Sunni law, the marriage contracted without witness is :

Under Sunni law a marriage requires two male witnesses, or one male and two female witnesses, who are sane, adult Muslims. A marriage contracted without witnesses is irregular (fasid), not void (batil): the defect is temporary and can be cured, but the marriage has no full legal effect until then.

Under Shia law no witnesses are required, which is why the school must be named.