, ▁ending ▁the ▁Rus so - T urk ish ▁War ▁( 1 8 7 7 – 1 8 7 8 ), ▁Russia ▁gained ▁considerable ▁land ▁in ▁what ▁is ▁now ▁eastern ▁Turkey ▁( ter med ▁Western ▁Armen ia ), ▁extending ▁the ▁Ott oman - Russ ian ▁front ier ▁south - west wards . ▁Russia ' s ▁g ains ▁of ▁Bat umi , ▁K ars ▁and ▁Ar d ah an ▁were ▁confirmed ▁by ▁the ▁Tre aty ▁of ▁Berlin ▁( 1 8 7 8 ), ▁though ▁it ▁was ▁comp elled ▁to ▁hand ▁back ▁part ▁of ▁the ▁area ▁around ▁Bay az id ▁( mod ern ▁Do ğ ub ay az ı t ) ▁and ▁the ▁Ele ş k irt ▁valley . ▁ ▁During ▁the ▁First ▁World ▁War ▁Russia ▁inv aded ▁the ▁eastern ▁areas ▁of ▁the ▁Ott oman ▁Empire . ▁In ▁the ▁cha os ▁following ▁the ▁ 1 9 1 7 ▁Russian ▁Revolution ▁the ▁new ▁Commun ist ▁government ▁hast ily ▁sought ▁to ▁end ▁its ▁invol vement ▁in ▁the ▁war ▁and ▁signed ▁the ▁Tre aty ▁of ▁Br est - L it ov sk ▁in ▁ 1 9 1 8 ▁with ▁Germany ▁and ▁the ▁Ott oman ▁Empire . ▁By ▁this ▁treat y , ▁Russia ▁handed ▁back ▁the ▁areas ▁gained ▁by ▁the ▁earlier ▁Tre aties ▁of ▁San ▁Stef ano ▁and ▁Berlin . ▁ ▁Se ek ing ▁to ▁gain ▁independence ▁from ▁both ▁emp ires , ▁the ▁pe op les ▁of ▁the ▁southern ▁C au cas us ▁had ▁declared ▁the ▁Trans c au cas ian ▁Democratic ▁Feder ative ▁Republic ▁in ▁ 1 9