hr ' s ▁chamber ▁music ▁is ▁a ▁series ▁of ▁no ▁fewer ▁than ▁ 3 6 ▁string ▁quart ets , ▁as ▁well ▁as ▁four ▁double ▁quart ets ▁for ▁two ▁string ▁quart ets . ▁He ▁also ▁wrote ▁an ▁ass ort ment ▁of ▁other ▁quart ets , ▁du os , ▁tri os , ▁qu int ets ▁and ▁se xt ets , ▁an ▁oct et ▁and ▁a ▁non et , ▁works ▁for ▁solo ▁viol in ▁and ▁for ▁solo ▁har p , ▁and ▁works ▁for ▁viol in ▁and ▁har p ▁to ▁be ▁played ▁by ▁him ▁and ▁his ▁wife ▁together . ▁ ▁Though ▁obsc ure ▁today , ▁Spo hr ' s ▁oper as ▁Fa ust ▁( 1 8 1 6 ), ▁Z em ire ▁und ▁Az or ▁( 1 8 1 9 ) ▁and ▁Jess onda ▁( 1 8 2 3 ) ▁remained ▁in ▁the ▁popular ▁re per toire ▁through ▁the ▁ 1 9 th ▁century ▁and ▁well ▁into ▁the ▁ 2 0 th , ▁when ▁Jess onda ▁was ▁b anned ▁by ▁the ▁Naz is ▁because ▁it ▁dep icted ▁a ▁European ▁hero ▁in ▁love ▁with ▁an ▁Indian ▁prin cess . ▁Spo hr ▁also ▁wrote ▁ 1 0 5 ▁songs ▁and ▁du ets , ▁many ▁of ▁them ▁collected ▁as ▁Deutsche ▁L ieder ▁( G erman ▁Songs ), ▁as ▁well ▁as ▁a ▁mass ▁and ▁other ▁ch oral ▁works . ▁ ▁Most ▁of ▁his ▁oper as ▁were ▁little ▁known ▁outside ▁of ▁Germany , ▁but ▁his ▁or ator ios , ▁particularly ▁Die ▁letzten ▁D inge ▁( 1 8 2 5 – 1 8