▁his ▁Ph D , ▁and ▁began ▁publishing ▁poetry ▁in ▁ 1 9 1 6 . ▁ ▁Frederick ▁Mort imer ▁Cla pp ▁joined ▁the ▁A viation ▁section ▁of ▁the ▁U . S . ▁Army , ▁prior ▁to ▁the ▁creation ▁of ▁the ▁air ▁force , ▁and ▁was ▁a ▁First ▁Lieutenant ▁in ▁the ▁Sign al ▁Corps ▁and ▁pilot ▁in ▁World ▁War ▁I . ▁When ▁he ▁returned ▁from ▁war , ▁Cla pp ▁published ▁art ▁historical ▁writ ings , ▁often ▁in ▁the ▁Pr inc eton ▁Journal , ▁" Art ▁Studies ." ▁In ▁ 1 9 2 6 , ▁Cla pp ▁became ▁chair ▁of ▁the ▁History ▁of ▁Art ▁and ▁Architecture ▁Department ▁at ▁the ▁University ▁of ▁Pitts burgh . ▁There , ▁he ▁developed ▁the ▁school ' s ▁art ▁library ▁and ▁phot ography ▁collection , ▁which ▁became ▁known ▁as ▁the ▁Fr ick ▁Fine ▁Arts ▁Library ▁and ▁now ▁res ides ▁in ▁the ▁Fr ick ▁Fine ▁Arts ▁Building ▁on ▁the ▁Oak land ▁campus . ▁He ▁was ▁named ▁advis er ▁to ▁the ▁Fr ick ▁Collection ▁in ▁ 1 9 3 1 , ▁and ▁o vers aw ▁the ▁development ▁of ▁the ▁Fr ick ▁residence ▁into ▁a ▁museum ▁in ▁ 1 9 3 3 , ▁h iring ▁the ▁architect , ▁John ▁Russell ▁Pope , ▁and ▁opening ▁the ▁museum ▁in ▁ 1 9 3 5 . ▁Frederick ▁Mort imer ▁Cla pp ▁was ▁officially ▁named ▁director ▁of ▁the ▁Fr ick ▁Collection ▁in ▁ 1 9 3 6 . ▁He ▁retired ▁in ▁ 1 9 5 1 ▁and ▁died ▁in ▁New ▁York ▁City ▁December ▁ 1 5 , ▁