The first (and last, by coincidence) was Margaret I of Denmark. (1353 - 1412) Founder of zhe Kalmar union. And no, she was not 'in' Iceland, but she did rule it.
The Denmark Strait separates Iceland and Greenland.
Denmark. Iceland isn't flat at all.
Yes, there are ferry services available from Iceland to Denmark.
iceland
They both are, yes. Are you thinking of Greenland? Iceland is not a part of Denmark - Greenland is.
No, there is no direct ferry service from Denmark to Iceland available.
Norway and Denmark
There are no direct ferry options from Iceland to Denmark. Travelers typically fly or take a combination of ferries and trains through other countries to reach Denmark from Iceland.
Denmark is under the rule of Denmark...
Copenhagen, when Iceland was ruled by Denmark.
Denmark.