Combine all of the spices, onions, garlic, oil and wine in a large roasting pan with a lid.
Cut up the octopus tentacles into large 3 inch pieces, removing any excess skin. Separate the skin from the head by pulling it apart, then cut into large pieces. (Make sure you remove the mouth & bone from the head).
Wash thoroughly, then add to the roasting pan.
Roast uncovered for approximately 1 hour. Cover then roast for another hour.
When the octopus is tender, add the potatoes and cook for another hour, or so. If the sauce is drying, you can add either more wine or some water.
The cooking time will vary depending on the size and thickness of the octopus. Adjust the time accordingly.
Taste the potatoes, then add more salt, or more spices if desired.