▁for ▁the ▁Dublin ▁Institute , ▁this ▁time ▁as ▁Ass istant ▁Professor . ▁Three ▁year ▁later , ▁he ▁became ▁Professor ▁of ▁Old ▁and ▁Middle ▁Irish ▁and ▁C elt ic ▁Phil ology ▁at ▁National ▁University ▁of ▁Ireland , ▁Gal way , ▁which ▁would ▁become ▁the ▁longest - h eld ▁position ▁of ▁his ▁career ▁( 1 9 6 6 – 1 9 9 4 ). ▁ ▁Mac ▁E oin ▁also ▁turned ▁to ▁politics ▁to ▁promote ▁the ▁Irish ▁language . ▁He ▁joined ▁the ▁movement ▁Gl ua ise acht ▁Ce arta ▁Sib h ial ta ▁na ▁Ga elt ach ta ▁in ▁ 1 9 6 9 ▁and ▁by ▁helping ▁to ▁set ▁up ▁local ▁comm itte es ▁in ▁the ▁Ga elt acht ▁area , ▁contributed ▁to ▁the ▁institution ▁of ▁the ▁Ú dar ás ▁na ▁Ga elt ach ta ▁in ▁ 1 9 7 9 . ▁ ▁The ▁Royal ▁Irish ▁Academy ▁made ▁him ▁a ▁member ▁in ▁ 1 9 7 5 . ▁As ▁professor ▁in ▁Dublin ▁and ▁Gal way , ▁Mac ▁E oin ▁and ▁his ▁fellow ▁staff ▁members ▁have ▁been ▁responsible ▁for ▁organ ising ▁a ▁number ▁of ▁national ▁and ▁international ▁con ferences , ▁not ably ▁the ▁Six th ▁International ▁Congress ▁of ▁C elt ic ▁Studies ▁( 1 9 7 9 ). ▁He ▁has ▁been ▁visit ing ▁professor ▁at ▁a ▁number ▁of ▁German ▁univers ities , ▁namely ▁those ▁of ▁Bonn ▁( 1 9 7 9 – 8 0 ), ▁Fre ib urg ▁( 1 9 8 5 ) ▁and ▁the ▁H umb old t ▁University ▁of ▁Berlin ▁( 1 9 9