Shakespeare’s sonnet 18 is one of the best know of his poems, first published in 1609 - though most likely written some years earlier.
With the famous opening lines ‘Shall I compare thee …’ the narrator wonders if the beauty of his beloved could be measured alongside something as splendid as a fine summer’s day.
He considers the possibility that the object of his devotion might not only be its equal but better. After all, the harsh winds can blast the buds on the trees and flowers, and the sun can sometimes be too hot, or its brightness dimmed. No matter how fair the day or season, there is always an inevitable decline in its charms. The ‘lease’ of summer is also often short – declining into autumn.
His beloved, however, is more ‘temperate’ - more calm and pleasing than ‘nature’s changing course untrimm’d’ – (untrimmed being a reference to the sails of a boat, the vessel being at the mercy of the wind when not aligned properly).
The message here is that ideas and thoughts can sometimes prove more enduring than those physical things we sometimes mistakenly perceive as reality. The so-called reality passes with time, but the ideas and memories that it inspired can remain.
With amazing self-confidence, the poet reflects on the permanence of his work (his eternal lines), and so even as the beauty of his beloved fades with the passage of time, it will grow and remain forever lovely through the vehicle of his poem – something which he presumes will be read ‘as long as men can breathe or eyes can see.’ He was right, of course. But how did he know?