Well, maybe 3.5 stars. Interesting premise and for the most part I think he did a fair job of extrapolating what kind of changes might occur should the Spanish Armada have won, not to mention using different characters than you usually see in historical pieces. And Strawberry was a very good take-off of Shakespeare's own Dogberry. 
 But the one thing that bugged me throughout was the relative freedom of William Cecil, Lord Burghley . I can sort of see sparing Elizabeth and keeping her locked up--a cruel sort of mercy--although I rather think Philip would have had her burned as a bastard heretic (but that's merely my opinion). But not this one of all her ministers. He should have been killed or at the very least imprisoned. Author's note states that according to historical record, Philip had not intended to kill the man; that I don't know since most of my reading on the Armada focused on the English side. But Turtledove never gave any sort of plausible reason! Only equally baffled Spanish dons. But it bugged me.