thanks for your mail. I found following information for you: 1) The DUDEN, a common German dictionary, contains, that the name Ahlschwede is develloped from the village "Ahlswede". This village lies west of Minden, which itself lies at the Border of the WESER-river. So the original name is Ahlswede, Ahlschwede is a later development. You can follow up traces of Ahlswede alond the river-line, with HAMELN as a place of concentration of this name. 2) In Niedersachsen there are 12 places called HAGEN (which means, a place surrounded by brushes as a security-tool). One HAGEN lies 5 km west of BAD PYRMONT (close to Hameln). And OTTENSTEIN lies 15 km east of BAD PYRMONT. So I suppose, your HAGEN may be this one.
So far for today. I will search for more information. Best regards,
PS:: HAMELN is the city of the famous "Rattenfaenger".