To avoid the imputation of too much vanity, (for all writers, and especially poets, will have some,) I will give but one other instance, in relation to the uniformity of the design.  I have observed, that the English will not bear a thorough tragedy; but are pleased, that it should be lightened with underparts of mirth.  It had been easy for me to have given my audience a better course of comedy, I mean a more diverting, than that of Antonio and Morayma; but I dare appeal, even to my enemies, if I, or any man, could have invented one, which had been more of a piece, and more depending on the serious part of the design.  For what could be more uniform, than to draw from out of the members of a captive court, the subject of a comical entertainment?  To prepare this episode, you see Dorax giving the character of Antonio, in the beginning of the play, upon his first sight of him at the lottery; and to make the dependence, Antonio is engaged, in the fourth act, for the deliverance of Almeyda; which is also prepared, by his being first made a slave to the captain of the rabble.

I should beg pardon for these instances; but perhaps they may be of use to future poets, in the conduct of their plays; at least, if I appear too positive, I am growing old, and thereby in possession of some experience, which men in years will always assume for a right of talking.  Certainly if a man can ever have reason to set a value on himself, it is when his ungenerous enemies are taking the advantage of the times upon him, to ruin him in his reputation.  And therefore, for once, I will make bold to take the counsel of my old master Virgil,

  Tu ne cede mails, sed contra audentior ito.

Footnotes: 
1.  There was a Portuguese prophecy to this purpose, which they applied
   to the expected return of Sebastian: 

Vendra et Incubierto, Vendra cierto; Entrera en el huerto, Per el puerto, Questa mas a ca del muro; Y’lo que paresce escuro, Se vra claro e abierto.

Two false Sebastians, both hermits, laid claim to the throne of Portugal.  One was hanged, and the other died in the galleys.  Vide Le Quien’s Histoire Generale de Portugal.—­There are two tracts which appear to regard the last of these impostors, and which may have furnished our author with some slight hints; namely, “The true History of the late and lamentable Adventures of Don Sebastian, King of Portugal, after his imprisonment at Naples until this present day, being now in Spain, at San Lucar de Barrameda.—­1602;” and, “A continuation of the lamentable and admirable Adventures of Don Sebastian, King of Portugal, with a Declaration of all his time employed since the Battle in Africk against the Infidels, 1578, until this present year 1603.  London, 1603.”  Both pieces are reprinted in the Harleian Miscellany, Vols IV. and V.

2.  The uncertainty of his fate is alluded to by Fletcher: