Conversation so far:
When did Carl Nielsen get married?
Carl Nielsen and Anne Marie Brodersen toured Italy together and married in St Mark's English Church, Florence, on 10 May 1891 before returning to Denmark.
What is Carl Nielsen's wife's name?
Carl Nielsen's wife was Anne Marie Brodersen.
How many children did Carl Nielsen and Anne Marie Brodersen have?
Carl Nielsen had three children.
What were Carl Nielsen's children's names?
Carl Nielsen's children were named Irmelin, Anne Marie, and Hans Børge.
Did Carl Nielsen have any other wives?
What were the name of Carl Nielsen's two illegitimate children?
Carl Nielsen had already fathered a son, Carl August Nielsen before he met Anne Marie. In 1912, an illegitimate daughter was born – Rachel Siegmann, about whom Anne Marie never learned.

Question: How long was he married to Anne Marie?
Self-contained rewrite: How long was Carl Nielsen married to Anne Marrie?