It would be hard if not outright impossible to overstate the impact Roman Emperor Constantine I had on the history of Christianity, Ancient Rome, and Europe as a whole. Best known as Constantine the Great, the kind of moniker only earned by rulers who have distinguished themselves in battle and conquest, Constantine remains an influential and controversial figure to this day. He achieved enduring fame by being the first Roman emperor to personally convert to Christianity.

On March 8, 1862, the newest era of naval warfare began. That day the CSS Virginia, an ironclad created out of the hull of the scuttled USS Merrimac by the Confederates, sailed down the Elizabeth River to Hampton Roads, where a Union blockade fleet was anchored. The wooden ships of the North were no match for the ironclad, which quickly rammed and sank the USS Cumberland.

J. D. Salinger might have been one of America's greatest 20th century authors, but only he knows for sure. As a young adult, Salinger wrote a number of short stories that were published during the 1940s in Story Magazine and his story "A Perfect Day for Bananafish" appeared in The New Yorker magazine to wide praise. Salinger followed that up with his most famous work, the 1951 novel The Catcher in the Rye, which was popular among adults and adolescents alike.

The Holy Grail is one of the most famous relics of Christianity, but also one of the least understood. Today, it is mostly associated with Christ's Last Supper, possibly used during the meal as a serving cup. The gospels in the New Testament specifically mention the Holy Chalice that Jesus used to serve wine, so it's no surprise that images of the Holy Grail depict a similar kind of cup.

A lot of ink has been spilled covering the lives of history's most influential figures, but how much of the forest is lost for the trees? In Charles River Editors' Legends of the Middle Ages series, readers can get caught up to speed on the lives of the most important medieval men and women in the time it takes to finish a commute, while learning interesting facts long forgotten or never known.