Since Leicester died in 1588, the poem obviously antedates the publication of Complaints. Edwin A. Greenlaw and others have interpreted it to refer to the "calling-in" of Mother Hubberds Tale, printed in Complaints following the Gnat.
Henry John Todd: "Possibly the Earl's displeasure might have been excited, in consequence of Spenser's pleading in behalf of Archbishop Grindal, who is believed to have incurred the Earl's enmity on account of his determination to prosecute and Italian physician, whom Leicester wished to protect, as a bigamist" Works of Spenser (1805) 1:lxxx.
Wrong'd, yet not daring to express my Pain,
To you (great Lord) the Causer of my Care,
In cloudy Tears my case I thus complain
Unto your self, that only privy are:
But if that any Oedipus, unware,
Shall chance, through power of some divining Spright,
To read the Secret of this Riddle rare,
And know the Purport of my evil Plight,
Let him be pleased with his own Insight,
Ne further seek to glose upon the Text:
For grief enough it is to grieved Wight,
To feel this fault, and not be further vext.
But what-so by myself may not be shown,
May by this Gnat's Complaint be easily known.
[Works, ed. Hughes (1715) 4:1148]