I am totally surprised by how old this portmanteau word is. In fact, it's older than the phrase portmanteau word! It goes back at least to the 17th century, when British poet Abraham Cowley penned "Colonel Tuke's Tragi-Comedy, The Adventures of Five Hours." It appears in 1822's The British Poets. Including Translations. Volume XIII: Cowley, Vol. I. In this case, I think "translation" means that the spelling and punctuation have been standardized (but hopefully not bowdlerized), considering how closely the spelling and punctuation of this poem matches today's expectations compared with other written works of the 17th century.
At any rate, here's the poem in its entirety:
Colonel Tuke's Tragicomedy,
The Adventures of Five Hours
As when our kings (lords of the spacious main)
Take in just wars a rich plate-fleet of Spain,
The rude unshapen ingots they reduce
Into a form of beauty and of use;
On which the conqueror's image now does shine,
Not his whom it belong'd to in the mine:
So, in the mild contentions of the Muse
(The war which Peace itself loves and pursues)
So have you home to us in triumph brought
The cargason of Spain with treasures fraught.
You have not basely gotten it by stealth,
Nor by translation borrow'd all its wealth;
But by a powerful spirit made it your own;
Metal before, money by you 'tis grown.
'Tis current now, by your adorning it
With the fair stamp of your victorious wit.
But, though we praise this voyage of your mind,
And though ourselves enrich'd by it we find;
We're not contented yet, because we know
What greater stores at home within it grow.
We've seen how well you foreign ores refine;
Produce the gold of your own nobler mine:
The world shall then our native plenty view,
And fetch materials for their wit from you;
They all shall watch the travails of your pen,
And Spain on you shall make reprisals then.