This could be of interest. My GG Granfather was Carl Frederick Lassen and he was indeed born in Schleswig-Holstein in 1850. There are other relatives that I have traced back to Meggerdorf but not on the Lassen side. I believe that Carl Frederick's father was Frederick Lassen. What is the Hamburg Passenger site URL? Do you know who Severt's father was? I would be happy to send you the info I have if you wish .... I am very interested in tracking the Lassens in Schleswig-Holstein.