Complex sentence: It is a long poem, 207 lines in length, divided into 16 sections referred to as cantos or strophes that range in length from 5 or 6 lines to as many as 53 lines.
Split into simpler sentences: It is a long poem, 207 lines in length. In its current form, it is divided into 16 sections referred to as cantos or strophes that range in length from 5 or 6 lines to as many as 53 lines.