If you’ve found a mortgage for an ancestor, try and determine if there was a record made of the mortgage being paid off.
In some locations these “pay-offs” are filed separately in the same office where the mortgages are recorded. They may be referred to as “releases” or some other word suggesting that the title to the real property is no longer subject to the mortgage payment. It may also be that the original record of the mortgage has a notation signed by an official or the original noteholder.
If there’s no indication the mortgage was paid off, consider searching for court records where the property was foreclosed upon. If that fails, search through land records for the property in question.