▁den ounced ▁as ▁an ▁ind ifferent ▁knock off ▁of ▁a ▁St . ▁Bernard — not ▁a ▁stable ▁and ▁recognized ▁bre ed — and ▁a ▁product ▁of ▁a ▁popular ▁f ad ▁or ▁fashion ▁for ▁large ▁and ▁strong ▁dogs , ▁f oment ed ▁in ▁part ▁by ▁Ess ig ' s ▁pro dig ious ▁market ing ▁skills ▁( he ▁gave ▁dogs ▁to ▁the ▁rich ▁and ▁famous ). ▁ ▁The ▁modern ▁look ▁of ▁the ▁Leon berger , ▁with ▁dark er ▁co ats ▁and ▁black ▁mask s , ▁was ▁developed ▁during ▁the ▁latter ▁part ▁of ▁the ▁ 2 0 th ▁century ▁by ▁re int rodu cing ▁other ▁bre eds , ▁such ▁as ▁the ▁New found land . ▁This ▁was ▁necessary ▁because ▁bre eding ▁stock s ▁of ▁the ▁Leon berger ▁were ▁seriously ▁affected ▁by ▁the ▁two ▁world ▁wars . ▁During ▁World ▁War ▁I , ▁most ▁Leon berg ers ▁were ▁left ▁to ▁f end ▁for ▁themselves ▁as ▁bre ed ers ▁fled ▁or ▁were ▁killed . ▁Report edly , ▁only ▁five ▁Leon berg ers ▁surv ived ▁World ▁War ▁I ▁and ▁were ▁b red ▁until ▁World ▁War ▁II ▁when , ▁again , ▁almost ▁all ▁Leon berg ers ▁were ▁lost . ▁During ▁the ▁two ▁world ▁wars , ▁Leon berg ers ▁were ▁used ▁to ▁pull ▁the ▁am mun ition ▁c arts , ▁a ▁service ▁to ▁the ▁bre ed ' s ▁country ▁that ▁resulted ▁in ▁the ▁Leon berg ers ' ▁near - dest ruction . ▁Karl ▁Stad el mann ▁and ▁Otto ▁Jos en h ans ▁are ▁cred ited ▁as ▁the ▁bre ed ' s ▁sav