From Sappho

The first several lines of Catullus's poem could seem to the average Roman reader to simply be a Latin translation of the Sappho 31 poem.  The visual imagery between the two poems is very similar, and the first two lines are nearly identical.  That is, until you reach line 7, with the mention of Lesbia.  After that, Catullus uses only a few more lines of Sappho, to describe how he feels about the situation.

Catullus has discussed in many of his previous poems about Lesbia's other men, but always with a comical disdain.  This poem is different from any of his previous ones about Lesbia, because it is the first sign of outright jealousy, and him admitting that he still has feelings for Lesbia, and is possibly not yet over her.  Catullus masks these feelings by translating Sappho.

The last stanza of the poem, which seems to be a quote said by Lesbia about Catullus, looks to me to be Catullus trying to make a point to Lesbia (Catullus? Trying to make a point?) that the idleness that she says is his poetry writing, is not idleness at all.  By comparing himself to a famous Greek Lyric poet such as Sappho, he is proving to Lesbia that this type of poetry is not one that he made up just to talk about their love affair, (among other things) but that it is one which has been used by other renowned poets from Ancient Greece, home of poetry and such arts.  By connecting himself to Sappho, he also shows that her saying "idleness ruined the kings and the cities of former times" is not true in this case.

On a side note, Ryan Gosling: the modern day Catullus.