▁K . ▁ 3 8 7 , ▁ 4 2 1 , ▁ 4 2 8 , ▁ 4 5 8 , ▁ 4 6 4 , ▁ 4 6 5 , ▁Op . ▁ 1 0 ▁( 1 7 8 2 – 1 7 8 5 ) ▁ ▁Moz art ▁returned ▁to ▁the ▁quart et ▁in ▁the ▁early ▁ 1 7 8 0 s ▁after ▁he ▁had ▁moved ▁to ▁Vienna , ▁met ▁Hay dn ▁in ▁person , ▁and ▁developed ▁a ▁friendship ▁with ▁the ▁older ▁composer . ▁Hay dn ▁had ▁just ▁published ▁his ▁set ▁of ▁six ▁quart ets , ▁Op . ▁ 3 3 , ▁which ▁are ▁thought ▁to ▁have ▁been ▁a ▁stim ulus ▁to ▁Moz art ▁in ▁returning ▁to ▁the ▁genre . ▁These ▁quart ets ▁are ▁often ▁regarded ▁as ▁among ▁the ▁p inn acles ▁of ▁the ▁genre . ▁String ▁Quart et ▁No . ▁ 1 4 ▁in ▁G ▁major , ▁" Spring ", ▁K . ▁ 3 8 7 ▁( 1 7 8 2 ) ▁String ▁Quart et ▁No . ▁ 1 5 ▁in ▁D ▁minor , ▁K . ▁ 4 2 1 / 4 1 7 b ▁( 1 7 8 3 ) ▁String ▁Quart et ▁No . ▁ 1 6 ▁in ▁E ▁major , ▁K . ▁ 4 2 8 / 4 2 1 b ▁( 1 7 8 3 ) ▁String ▁Quart et ▁No . ▁ 1 7 ▁in ▁B ▁major , ▁" H unt ", ▁K . ▁ 4 5 8 ▁( 1 7 8 4 ) ▁String