How do we know when Shakespeare wrote Othello?

In Act 1, Scene 3, lines 263-277 of Othello, the titular character adds on to his wife Desdemona’s plea to go with him to war in Cyprus. This speech clearly marks Othello as a play from William Shakespeare’s later works rather than his early works. The main and most important distinctions are in style. Whether earlier or later in his career, all of Shakespeare’s works are brilliant works written in iambic pentameter. However, there are subtle distinctions in the craft. In the speeches of his older plays, the insistent iambic pentameter often interrupts the enjambed line. The last beat of the iambic pentameter would stop the line, despite the continuance of the sentence onto the next line. In his later career, more variation in the iambic pentameter made the speech more conversational, rather than poetic. For instance, Othello says “And heaven defend your good souls that you think/I will your serious and great business scant/When she is with me” (lines 269-71). The speech wraps nicely from line to line with no forced pauses from the meter. Another line that does this is “Nor to comply with heat—the young affects/In me defunct—and proper satisfaction,/But to be free and bounteous to her mind” (lines 266-8). The syntax of the line does not seem broken by the line breaks. If these lines are read out loud, it would be difficult to discern where the line breaks are. This was definitely more of a feature in Shakespeare’s later period plays. Another way he did this was by adding an extra, unaccented syllable at the end of the line. One example is the line “Vouch with me, heaven, I therefor beg it not” (line 264). It has five iambs, and then one last unaccented word. This is the same with the line “In me defunct—and proper satisfaction” (line 267). The last syllable of “satisfaction” is an extra one for iambic pentameter. The effect of this is that the emotion of the speech sounds more authentically conversational, like Othello is engaged in a real-life discussion. The speech is more disconnected, like genuine dialogue would be. It is obviously not formal rhetoric or rehearsed, written poetics. Thus, all the stylistic clues of this speech suggest that Othello is late rather than early Shakespeare.