Keep, Galileo, to thy thought,
And nerve thy soul to bear;
They may gloat o’er the senseless words they wring
From the pangs of thy despair:
They may veil their eyes, but they cannot hide
The sun’s meridian glow;
The heel of a priest may tread thee down,
And a tyrant work thee woe;
But never a truth has been destroyed:
They may curse it, and call it crime;
Pervert and betray, or slander and slay
Its teachers for a time.
But the sunshine aye shall light the sky,
As round and round we run;
And the truth shall ever come uppermost,
And justice shall be done.

Charles Mackay (1814-1889) Scottish poet, journalist, song writer

Poem (1847), “Eternal Justice,” st. 4
    (Source)

Mackay's book Voices from the Mountain was published in 1847. The earliest rendition of the poem I can find in a publication is from The Harbinger, Vol. 5, No. 13 (1847-09-04).