The idea that the Civil War might end quickly evaporated in mid-December 1862 when the Union Army met a deeply sobering defeat at the Battle of Fredericksburg.

After the immense carnage of Antietam in September 1862, President Abraham Lincoln installed General Ambrose Burnside as commander of the Army of the Potomac. It was hoped that Burnside could quickly crush the southern army, which had regrouped in Virginia.

Burnside moved his troops across a river and attacked the town of Fredericksburg on December 13, 1862. Things began to go wrong, and when the day ended the Union Army was battered. One of its most illustrious units, the Irish Brigade, was essentially destroyed.

When Lincoln heard news of the disaster he was said to be in agony. Across the north the Christmas season turned into a time of mourning and apprehension. The Battle of Fredericksburg made it clear the Civil War would not end anytime soon.

Photograph: General Ambrose Burnside/Library of Congress

We think of Christmas traditions as being timeless, but many of our Christmas traditions are rooted firmly in the 19th century. In fact, someone alive 200 years ago would not even recognize how we celebrate Christmas.

The Christmas tree was an obscure ethnic tradition that really became popular because of Prince Albert, the very stylish husband of Britain's Queen Victoria. Once the British royals brought a tree into Windsor Castle word spread to New York, and Christmas trees started to catch on in America.

And Santa Claus may be based on an ancient legend, but the way we think of Santa is really based on the creations of writer Washington Irving and the famed political cartoonist Thomas Nast.

And, yes, Virginia, the legend of Santa was made immortal in the 1890s. A classic editorial in the New York Sun, in response to a letter by a young girl, made Santa Claus an institution.

Much of the holiday season owes a great debt to traditions which only began in the 1800s.

The husband of Britain's Queen Victoria was actually a German prince who was initially considered an interloper in British society. Albert eventually gained a royal title, Prince Consort, and became a trusted and crucial adviser to his wife, who, of course, happened to be one of the most powerful people on earth.

Prince Albert was known for his keen interest in technology and the arts, and there's no doubt he was a force for social progress in the mid-1800s. He even helped make popular a tradition on our minds today, the Christmas tree.

His death at a relatively young age shattered Queen Victoria, who was only seen in the black garb of a widow for the remaining four decades of her life. She may have ruled much of the known world, but she was always deeply pained by the loss of her beloved Albert.

Illustration: Albert, Prince Consort of Britain/Library of Congress

Today marks the 150th anniversary of a major event that helped spark the Civil War, the hanging of radical abolitionist John Brown.

Historian David S. Reynolds, who has written extensively about Brown and the mid-1800s, has published a thoughtful and provocative Op-Ed article in the New York Times noting how Brown's importance has been devalued over time.

Reynolds makes some valid points, one of which is that Brown, while he seems like an unbalanced fanatic today, was actually respected by a number of people during his own life. Of course, some of the people who knew him well, including Frederick Douglass, were extremely skeptical of his plans to seize a federal arsenal and spark a slave rebellion.

When Brown was executed, church bells tolled throughout the north. In Massachusetts, both Henry David Thoreau and Ralph Waldo Emerson spoke at a memorial service for him. And the controversy over John Brown accelerated the fraying of the nation, which would erupt in Civil War less than a year and a half later.

Illustration: John Brown/Library of Congress