atic ▁development ▁of ▁the ▁opera ▁meant ▁a ▁sea - change ▁from ▁the ▁Met ast as ian ▁prim acy ▁of ▁the ▁aria ; ▁in ▁Ross ini ' s ▁works , ▁solo ▁a rias ▁progress ively ▁take ▁up ▁a ▁smaller ▁proportion ▁of ▁the ▁oper as , ▁in ▁favour ▁of ▁du ets ▁( also ▁typically ▁in ▁cant abile - c ab alle tta ▁format ) ▁and ▁ens emb les . ▁ ▁During ▁the ▁late ▁ 1 8 th - century , ▁cre ators ▁of ▁opera ▁buff a ▁had ▁increasing ly ▁developed ▁dram atic ▁integration ▁of ▁the ▁finales ▁of ▁each ▁act . ▁Final es ▁began ▁to ▁" sp read ▁backwards ", ▁taking ▁an ▁ever ▁larger ▁proportion ▁of ▁the ▁act , ▁taking ▁the ▁structure ▁of ▁a ▁mus ically ▁continuous ▁chain , ▁accompanied ▁throughout ▁by ▁or chestra , ▁of ▁a ▁series ▁of ▁sections , ▁each ▁with ▁its ▁own ▁characteristics ▁of ▁speed ▁and ▁style , ▁mount ing ▁to ▁a ▁cl am orous ▁and ▁vig orous ▁final ▁scene . ▁In ▁his ▁com ic ▁oper as ▁Ross ini ▁brought ▁this ▁technique ▁to ▁its ▁peak , ▁and ▁extended ▁its ▁range ▁far ▁beyond ▁his ▁prede cess ors . ▁Of ▁the ▁finale ▁to ▁the ▁first ▁act ▁of ▁L ' ital iana ▁in ▁Al ger i , ▁Tar us kin ▁writes ▁that ▁"[ r ] unning ▁through ▁almost ▁a ▁hundred ▁pages ▁of ▁vocal ▁score ▁in ▁record ▁time , ▁it ▁is ▁the ▁most ▁concentr ated ▁single ▁do se ▁of ▁Ross ini ▁that ▁there ▁is ." ▁ ▁Of ▁greater ▁consequence ▁for ▁the ▁history ▁of ▁opera ▁was ▁Ross ini