leg ▁Pro k of iev ▁( the ▁composer ' s ▁young est ▁son ). ▁ ▁Catalog ▁In cons isten cies ▁ ▁There ▁is ▁some ▁disag re ement ▁when ▁it ▁comes ▁to ▁assigning ▁the ▁proper ▁op us ▁number ▁to ▁this ▁son ata . ▁Pro k of iev ▁marked ▁the ▁son ata ' s ▁manuscript ▁itself ▁with ▁Op us ▁ 1 3 3 , ▁but ▁when ▁dict ating ▁a ▁list ▁of ▁his ▁final ▁compos itions ▁to ▁his ▁second ▁wife ▁just ▁before ▁he ▁died , ▁he ▁told ▁her ▁that ▁the ▁son ata ▁was ▁to ▁be ▁Op us ▁ 1 3 4 . ▁Some ▁sch ol ars , ▁such ▁as ▁Vladimir ▁Blo k , ▁believe ▁that ▁the ▁correct ▁op us ▁number ▁is ▁the ▁one ▁found ▁on ▁the ▁manuscript ▁itself ▁– ▁yet ▁a ▁cons ensus ▁was ▁never ▁reached ▁and ▁therefore ▁the ▁Son ata ▁for ▁Solo ▁C ello ▁can ▁now ▁be ▁found ▁as ▁Op us ▁ 1 3 3 ▁or ▁Op us ▁ 1 3 4 ▁depending ▁on ▁the ▁particular ▁catalog , ▁edition , ▁or ▁recording . ▁ ▁In ▁addition ▁to ▁the ▁incons istent ▁op us ▁number , ▁the ▁son ata ▁is ▁often ▁catalog ed ▁as ▁" S on ata ▁for ▁Solo ▁C ello ▁in ▁C ▁minor ". ▁This ▁would ▁likely ▁have ▁made ▁sense ▁if ▁Pro k of iev ▁had ▁completed ▁the ▁composition , ▁but ▁no ▁part ▁of ▁the ▁ext ant ▁manuscript ▁is ▁in ▁the ▁key ▁of ▁in ▁C ▁minor ▁and ▁Blo k ' s ▁reconst ruction ▁of ▁the ▁son ata ▁is ▁clearly ▁based ▁in ▁the ▁key ▁F ▁minor