9 5 0 ) ▁and ▁the ▁C athedral ▁School ▁( 1 9 4 6 – 1 9 5 0 ) ▁effective ▁in ▁September ▁ 1 9 5 0 . ▁ ▁St . ▁Mark ' s ▁is ▁the ▁result ▁of ▁this ▁mer ger , ▁and ▁it ▁was ▁immediately ▁and ▁robust ly ▁supported ▁by ▁some ▁of ▁Dallas ' s ▁most ▁successful ▁business men ▁of ▁the ▁post - World ▁War ▁II ▁era . ▁Begin ning ▁in ▁the ▁ 1 9 5 0 s , ▁for ▁example , ▁two ▁of ▁the ▁found ers ▁of ▁Texas ▁Inst ru ments ▁don ated ▁a ▁total ▁of ▁nearly ▁$ 5 0   mill ion , ▁helping ▁to ▁create ▁the ▁solid ▁end ow ment ▁and ▁modern ▁campus . ▁By ▁the ▁ 1 9 6 0 s , ▁Time ''' ▁magazine ▁called ▁St . ▁Mark ' s ▁the ▁" best ▁equ ipped ▁day ▁school ▁in ▁the ▁country ." ▁ ▁The ▁school ▁today ▁ ▁In ▁contrast ▁to ▁the ▁Terr ill ▁School , ▁which ▁was ▁created ▁and ▁spe ar head ed ▁by ▁its ▁e pon ym ous ▁founder ▁( and ▁then ▁failed ▁after ▁he ▁died ), ▁St . ▁Mark ' s ▁has ▁been ▁driven ▁by ▁don ors , ▁most ▁of ▁whom ▁have ▁act ively ▁served ▁on ▁its ▁board ▁of ▁trust ees . ▁As ▁D ▁Magazine ▁once ▁assert ed , ▁" there ▁are ▁some ▁prep ▁schools ▁where ▁the ▁head master ▁emb od ies ▁the ▁institution ’ s ▁trad itions ▁and ▁goals . ▁St . ▁Mark ’ s ▁is ▁not ▁one ▁of ▁them . ▁St . ▁Mark