Out of the church she followed them
With a lofty step and mien:
His bride was like a village maid,
Maude Clare was like a queen.
Rossetti begins abruptly, as if in the middle of a story, a device known as  in medias res  or in the middle of things; a hook to pull the reader in. The wedding is over, usually the place where the story ends. 
 The poem opens with a  trochee , that is a metrical foot comprising one stressed followed by one unstressed syllable. The traditional ballad style is written in  iambs , that is unstressed followed by stressed syllables. So, Rossetti is suggesting to the reader that this may be more than a simple ballad. 

Maude Clare