The sonnet has been much more important. In general, an English sonnet has fourteen lines of iambic pentameter with 
some kind of interlocking rhyme scheme. 

The two most popular variants are 

the Italian sonnet (an eight-line octave rhyming abbaabba and a six line sestet with a variety of possibilities: 
for example cdecde, or cdcdee, or cdeedc, or cddcee) 

and 

the Shakespearean sonnet (three quatrains rhyming abab, cdcd, efef, and a final couplet: gg).