Write a summary of Shakespeare's Sonnet 55.

Through the indestructibility of verse, the poet seeks to lend his beloved immortality. This is main idea of Shakespeare’s Sonnet 55.

Its first quatrain begins with the poet’s bold declaration that this piece of verse “shall outlive” “marble” or “the gilded monuments of princes.” During the Elizabethan period, the portraits of the members of the royal family were often carved on the stone cover of a coffin after their death. These memorials were gilded monuments made out of durable stone.

The poet, however, claims that the durability of these monuments would surrender to the effect of time, unlike this verse written on a piece of paper.

Not marble, nor the gilded monuments 
Of princes, shall outlive this powerful rhyme;

Calling time “sluttish,” the poet may be suggesting that time is faithful to none, kings or queens. It continues with its consistent and steady pace, indifferent to anything that happens on the earth. With time, these well-carved portraits, though belonging to royals or aristocrats, would get smeared and worn out. They would lose their sheen and splendor.

However, the contents of this sonnet are beyond the destructive effects of time. And, therefore, in this poem, his beloved “shall shine more bright” than the precious statues.  

In the second quatrain, the poet says that during “wasteful wars,” the monuments are demolished. The magnificent structures displaying the artistic skills of sculptors are turned to dust.

So, the poet has decided to keep his beloved safe till eternity in his verse. It’s because his verse couldn't be harmed even by the spear of Mars, the Greek God of war. As his words are indestructible even in fire, the poet calls this poem “the living record of your memory.”

In the final quatrain, the poet claims that even death wouldn't be able to harm his beloved. It’s because her essence is contained in this verse, and poetry is not a subject to death. Generation after generation would remember her until “the ending doom.” 

The final couplet sums up the main theme of the sonnet:

So, till the judgment that yourself arise, 
You live in this, and dwell in lovers' eyes.

It says that the poet’s beloved would “live in this” sonnet “till the judgment” Day. The confident poet assures his beloved that through his “powerful rhyme” he has made her immortal. Immortality is something that no king could buy himself with any quantity of precious stones or wealth. This is the strength of great poetry - that with its indestructibility, it can make its subject immortal.