RE: Mecklenburg Kirchenbücher by Franz Schubert

Can anyone give me some historical background on Franz Schubert's
Kopulationsregisters of Mecklenburg Kirchenbücher? Which parishes do his
indexes include? Do his indexes include information only from parish
marriage registers that had already previously been indexed? I can't imagine
that he, alone, compiled indexes for all the parishes in Mecklenburg for over
the 150-yr. span his books cover!

Thanks for the history!

Julie