8 , ▁O lt i ▁was ▁nomin ally ▁part ▁of ▁Democratic ▁Republic ▁of ▁Georgia ▁but ▁it ▁was ▁ruled ▁by ▁Turkish ▁war l ords . ▁In ▁ 1 9 1 9 - 1 9 2 0 , ▁O lt u ▁was ▁a ▁part ▁of ▁First ▁Republic ▁of ▁Armen ia . ▁In ▁ 1 9 2 0 ▁the ▁Turkish ▁arm ies ▁in ▁Eastern ▁An atol ia ▁led ▁by ▁Kaz ı m ▁Kar ab ek ir ▁inv aded ▁Armen ia ▁during ▁the ▁Turkish ▁War ▁of ▁National ▁Liber ation ▁and ▁occupied ▁O lt u , ▁a ▁territorial ▁gain ▁which ▁was ▁confirmed ▁in ▁subsequent ▁treat ies ▁signed ▁between ▁the ▁Tur ks ▁and ▁the ▁S ovi ets . ▁ ▁The ▁primary ▁historical ▁sight ▁in ▁O lt u ▁is ▁the ▁castle , ▁which ▁covers ▁the ▁top ▁of ▁a ▁rock y ▁out c rop . ▁Its ▁walls ▁are ▁fort ified ▁by ▁large ▁round ▁to wers ▁and ▁sal ients , ▁including ▁an ▁impos ing ▁tal us ▁at ▁the ▁south west . ▁A ▁circuit ▁wall ▁once ▁extended ▁from ▁the ▁out c rop ▁to ▁protect ▁a ▁small ▁ad jo ining ▁settlement . ▁The ▁medieval ▁for tr ess ▁is ▁the ▁result ▁of ▁two ▁major ▁periods ▁of ▁construction ▁between ▁the ▁ 7 th ▁and ▁the ▁ 1 1 th ▁centuries ; ▁major ▁rep airs ▁were ▁undert aken ▁by ▁the ▁Turkish ▁Corps ▁of ▁Engine ers ▁in ▁ 1 9 7 7 . ▁At op ▁the ▁north ▁tower ▁are ▁the ▁remains ▁of ▁a ▁Georg ian ▁hex acon ch ▁church ▁in ▁which ▁a ▁fragment ▁of ▁a ▁ 7 th