A line in the play that regards "These late eclipses in the sun and moon" appears to refer to a phenomenon of two eclipses that occurred over London within a few days of each other—the lunar eclipse of 27 September 1605 and the solar eclipse of 12 October 1605. This remarkable pair of events stirred up much discussion among astrologers. Edmund's line "A prediction I read this other day…" apparently refers to the published prognostications of the astrologers, which followed after the eclipses. This suggests that those lines in Act I were written sometime after both the eclipses and the published comments.