Sovay is a traditional English folk song (Roud 7, Laws N21) about a young woman who dresses and arms herself as a highwayman in order to test her suitor.
In disguise she robs her suitor of nearly all his possessions, but even under threat of death he refuses to give up the gold ring given by Sovay, thus proving his devotion.
She initially becomes a highwayman to test the depth of her fiance's love for her, then to save her father and finally because she enjoys the power and freedom provided by her male attire.
The song uses an adapted form of the original's main melody, but Bird's lyric has little-to-no relation, appearing to be a rhapsody on the spiritual fight against socio-political backsliding.
The Kate Bush song "Babooshka" in which a wife disguises herself to test her husband's loyalty was inspired by the story of Sovay.