There are lots of Irish tunes from the 18th century and a few of earlier date, but for songs, there don't seem to be any earlier than one printed in 1716 from John Able's singing, and "Aileen Aroon" from Kitty Clive in 1742. There are a few in English from the later 18th century, e.r., "Croppies lie Down".

But few of those known in the 18th century were 'historical', e.g., "The Night Before Larry was stretched", "Oonagh's/Una's Waterfall/Lock", "Black Joke". "Larry Grogan" was a real person, as was "Captain MaGan" so you might call that a historical song (Others for which Carolan composed tunes are noted or given in Donal O'Sulivan's 'Carolan'). See the Irish song section in the Scarce Songs 1 file on my website for others, and also see the Irish tune index on my website. I wasn't too careful in noting which tunes were published with the songs to them.
In Nicolas Carolan's notes to the Neals' Collection of Irish tunes, c 1724, Carolan notes what tunes had early songs to them, but most (none?) are not 'historical'.
www.erols.com/olsonw