The singer dreams of Richmond prison and Erin as a woman weeps for the loss "of her Green Linnet Davitt ashtore." She sings that he was trapped by the fowler, refused bail, and was caged nine years. The singer wakes to find the dream true.
Zimmermann: In Irish "a stoir" = my treasure. - BS
Although Michael Davitt (1846-1905) did spend many years in involuntary servitude, he never spent nine consecutive years in prison. AFenian from 1865, he was convicted in 1870 of gun-running and sentenced to fifteen years. In 1877, he was given a ticket-of-leave, and went on to found the Land League (for which see, e.g. "The Bold Tenant Farmer"). He ended up imprisoned again for just over a year in 1881-1882.
For a discussion of this type of song as a example of the genre known as the "aisling," see the notes to "Granuaile." - RBW