4 6 ) ▁by ▁Robert ▁Gra ves . ▁Other ▁recent ▁bi ographical ▁novel ▁series , ▁include ▁Con quer or ▁and ▁Emperor ▁by ▁Con n ▁I gg ul den ▁and ▁Cic ero ▁Tr il ogy ▁by ▁Robert ▁Harris . ▁ ▁Historical ▁myster ies ▁ ▁Historical ▁myster ies ▁or ▁" histor ical ▁wh od un its " ▁are ▁set ▁by ▁their ▁authors ▁in ▁the ▁distant ▁past , ▁with ▁a ▁plot ▁that ▁which ▁involves ▁the ▁solving ▁of ▁a ▁mystery ▁or ▁crime ▁( us ually ▁murder ). ▁Though ▁works ▁combining ▁these ▁gen res ▁have ▁existed ▁since ▁at ▁least ▁the ▁early ▁ 1 9 0 0 s , ▁many ▁credit ▁Ell is ▁Peters ' s ▁Cad f ael ▁Chron icles ▁( 1 9 7 7 – 1 9 9 4 ) ▁with ▁popular izing ▁them . ▁These ▁are ▁set ▁between ▁ 1 1 3 7 ▁and ▁ 1 1 4 5 ▁A . D . ▁The ▁increasing ▁popular ity ▁of ▁this ▁type ▁of ▁fiction ▁in ▁subsequent ▁dec ades ▁has ▁created ▁a ▁distinct ▁sub gen re ▁recognized ▁by ▁both ▁publish ers ▁and ▁libraries . ▁ ▁Historical ▁rom ance ▁and ▁family ▁sag as ▁ ▁Rom antic ▁them es ▁have ▁also ▁been ▁port rayed , ▁such ▁as ▁Doctor ▁Zh iv ago ▁by ▁Bor is ▁Pas tern ak ▁and ▁ ▁G one ▁with ▁the ▁Wind ▁by ▁Margaret ▁Mitchell . ▁One ▁of ▁the ▁first ▁popular ▁historical ▁roman ces ▁appeared ▁in ▁ 1 9 2 1 , ▁when ▁Ge or get te ▁He yer ▁published ▁The ▁Black ▁M oth , ▁which ▁is ▁set ▁in