Overview
Heptameter is a type of meter where each line of verse contains seven metrical feet. It was used frequently in Classical prosody, and in English, the line was used frequently in narrative poetry since the Romantics. The meter is also called septenary, and this is the most common form for medieval Latin and vernacular verse, including the Ormulum. Its first use in English is possibly the Poema Morale of the twelfth/thirteenth century.
An example from Lord Byron's Youth and Age:
'Tis but as ivy-leaves around the ruin'd turret wreathe,
All green and wildly fresh without, but worn and gray beneath.
O could I feel as I have felt, or be what I have been,
Or weep as I could once have wept o'er many a vanish'd scene,-
As springs in deserts found seem sweet, all brackish though they be,
So midst the wither'd waste of life, those tears would flow to me!
From Wikipedia (CC BY-SA 4.0).