A common trope of English folk songs. In it, a sailor returns home after seven years, usually disguised. He meets his betrothed and asks for her hand. She proves herself true by refusing this stranger's offer. He reveals his identity, usually by bringing out a broken ring, handkerchief, locket, or other, and the two fall into each other's arms etc etc
The period of separation is almost always seven years, since that was the minimum length of time for a sailor's apprenticeship, whether pressed upon or voluntary. May is always the month (if it isn't June) because it is the beginning of Spring, and since it's the only month of the year in England where it's warm enough to be bothered to be amorous.
Broken token songs:
Banks of Claudy
The Broken Token
John Riley
The Young and Single Sailor
Down by the Seaside
Like many folk songs, knowing when words constitue a variation or a different song is difficult. The names above are distinguishing phrases of songs with very similar structures and words. The same words are also sung to different tunes.
Hannah James with Sam Sweeney sang "Young and Single Sailor" in their album Catches and Glees (2009) - https://www.youtube.com/watch?v=cLbPffK6pr8
The Young Tradition sang "Banks of Claudy" in Oberlin (1968) - https://www.youtube.com/watch?v=8A5HDDx9YoY