Original: During the reorganization of the districts in 1969 several of the municipalities in the district were merged to become cities, however the district itself was only modified minimally, and also in the second reorganization 1974 it stayed nearly in the same borders as in 1817.
Simplified: During the reorganization of the districts in 1969 several of the municipalities in the district were joined together to become cities, but the district itself was only changed a little bit.