LASST UNS ERFREUEN derives its opening line and several other melodic ideas from GENEVAN 68 (68). The tune was first published with the Easter text "Lasst uns erfreuen herzlich sehr" in the Jesuit hymnal Ausserlesene Catlwlische Geistliche Kirchengesänge (Cologne, 1623). LASST UNS ERFREUEN appeared…