There's been endless (and often fruitless) debate over exactly what "Romantic" means whether it's simply a periodic designation, whether it refers to a movement, or to shared characteristics.
English Romanticism is sometimes held to have begun in the mid-to-late eighteenth century, although some use the date of the publication of Wordsworth and Coleridge's Lyrical Ballads in 1798 as a convenient starting point. A popular ending point is 1832, the date of the passage of the Reform Bill, although some extend it through the beginning of Victoria's reign in 1837.
The traditional canon of the six major Romantic poets consists of William Blake, William Wordsworth, Samuel Taylor Coleridge, Lord Byron, John Keats, and Percy Bysshe Shelley. Older studies, in fact, tend to treat these six male poets as the only writers of the Romantic period worth reading. In recent years, though, critical attention has turned to long-neglected authors, especially women authors, such as Charlotte Smith, Anna Letitia Barbauld, Letitia Elizabeth Landon, Mary Robinson, and Joanna Baillie.
The focus on the "big six" has also put nearly all the attention on lyric poetry; again, critics have recently been looking at other modes and genres. The major novelists of the period are Sir Walter Scott and Jane Austen; other major prose writers include Hazlitt, Lamb, and De Quincey.
Don't be caught using "Romantic" as if it had much to do with modern romance novels. There's a long, complicated (and interesting) history that can explain why they share a term, but don't assume that Coleridge's poems or Hazlitt's essays have anything to do with heaving bosoms and Fabio.
Note: This guide is still in the early stages of development.
Three question marks mean I have to write more on the subject. Bear with me.