Alexandrine Poetry Type is a line of poetry that has 12 syllables and derives from a medieval romance about Alexander the Great that was written in 12-syllable lines. An alexandrine is used to describe a line of poetic meter.

http://www.types-of-poetry.org.uk/

I liked this one, very dramatic. So Alexandrine is similar in parameters to the classic Shakespearian iambic pentameter, just 2 additional syllables and no requirement for arrangment of stressed syllables. Thanks for the poetry lesson!