Paddy Miles comes from Ireland to America. On St Patrick's day he wears the hat "wore for more than ninety years ... From my father's great ancestors." He plans to return to Ballymore with "the hat my father wore"
Zimmermann: "It has been noted that 'much of the pugnacity has gone from the music played on the 12th day of July' [S.H. Bell _Erin's Orange Lily_, p. 14]; there is a tendency to replace the most violent ballads by innocuous songs such as 'The Ould Orange Flute' or 'The Sash my Father Wore'. 'The Ould Orange Flute' appeared on nineteenth century broadsides. The other song ['The Sash my Father Wore'] is more recent; it was probably the paraphrase of a non-political song, 'The Hat my Father Wore'. A nationalist version, quite different in character but singable to the same tune, appeared in _The Shan Van Vocht_, August 1896." The "Donagh MacDonagh Song Collection" at tripod.lycos site includes a version of "The Hat My Father Wore" that has the singer exiled "For the joining of the Brotherhood in the year of '64"; the tune for MacDonagh's version is "The Sash my Father Wore." It is clear that "The Sash" is an adaptation of "The Hat," or vice versa. - BS
According to Spaeth, _A History of Popular Music in America_, p. 331, William ("Billy") Jerome and Jean Schwartzin 1909 published a song"The May My Father Wore on St. Patrick's Day." That can hardly be the original of this, but I don't know how the one influenced the other. - RBW