on ▁( 2 5 ▁June ▁ 1 8 7 8 ▁- ▁ 2 3 ▁June ▁ 1 9 5 9 ) ▁was ▁a ▁French ▁composer , ▁cho ir ▁conduct or , ▁and ▁music ▁educ ator . ▁His ▁compos itional ▁output ▁consists ▁of ▁six ▁anti ph ons ▁for ▁strings ▁and ▁organ , ▁one ▁mass , ▁one ▁bal let , ▁and ▁several ▁art ▁songs . ▁ ▁Born ▁in ▁Paris , ▁Gall on ▁was ▁the ▁elder ▁brother ▁of ▁composer ▁No ël ▁Gall on . ▁He ▁had ▁a ▁long ▁association ▁with ▁the ▁Paris ▁Conserv atoire , ▁first ▁as ▁a ▁student , ▁then ▁as ▁the ▁director ▁of ▁concert s ▁( 1 9 0 6 - 1 9 1 4 ), ▁and ▁then ▁as ▁a ▁fac ulty ▁member ▁from ▁ 1 9 1 9 ▁to ▁ 1 9 4 9 . ▁A ▁professor ▁of ▁harm ony , ▁he ▁taught ▁such ▁notable ▁mus icians ▁as ▁El sa ▁Bar raine , ▁Paul ▁B onne au , ▁Henri ▁Ch all an , ▁Georges ▁D and el ot , ▁Jean - Y ves ▁Daniel - Les ur , ▁Jean ne ▁Dem ess ieux , ▁Pierre ▁Der v aux , ▁Maurice ▁Dur uf lé , ▁Henri ▁D ut ille ux , ▁Ul vi ▁C em al ▁Er kin , ▁Jean ▁H ube au , ▁P au le ▁Maurice , ▁Oliv ier ▁Mess ia en , ▁Jean ▁Riv ier , ▁Pierre ▁San can , ▁and ▁Paul ▁T ort el ier . ▁He ▁was ▁the ▁cho ir ▁master ▁at ▁the ▁Paris ▁Opera ▁from ▁ 1 9