The Gettysburg Address is one of the most famous speeches ever given in the history of the United States. The speech was given by President Abraham Lincoln who delivered it during the American Civil War at Gettysburg. It was given after a military cemetery was dedicated to all of the Union soldiers who died during their encounter with the Confederate army at Gettysburg. This took place in the year 1863 on the 19th of November. Although President Lincoln was not the major speaker for the day, he was nevertheless asked to deliver a few words. In his address, Abraham Lincoln clearly declared that the purpose of the Civil War was to establish the principles of democracy and liberty in the United States. Although the Gettysburg Address was only two minutes long, it was one of the finest addresses a leader has ever given to his nation in times of war.
Well, this is a question that begs an involved answer.
The United States was involved in a civil war at the time President Lincoln. I won't go into the politics and motives behind the war, but I will attempt to answer your question as best as possible.
In July, 1863, the armies of the North and the South met at Gettysburg, Pennsylvania. A three-day battle ensued. Casualties were, for our modern-day thinking, unbelievably high (in the range of 25,000).
In November of that year, a special dedication of the battlefield was made, and Abraham Lincoln was one of the guest speakers. In two and a half minutes, he delivered his thoughts that revealed his views on the value of representative government and the cost of preserving it for all Americans.
So, in summation, he wrote the Gettysburg Address to dedicate the battlefield to the memory of those who struggled and died there so that all Americans can remember what happened in our history.
Gettysburg was a synopsis of Lincoln's Lyceum address and was designed to place the sacrifice of the men who died there in the greater context of the still relatively new nation they were trying to preserve, in the face of the "eagles" and "caesars" who would tear it down. It can also be argued that Lincoln himself was one of those caesars who was making his mark by freeing the slaves (again, see the Lyceum speech).
Abraham Lincoln wrote the Gettysburg Address, because there was one of the worst battles in the history of America. Especially considering that it was all Americans who were fighting. Anyways, during the Civil War, approximately 600,000 men died. That inspired Lincoln to write his speech, dedicating the battlefield to anyone who partook in the war.
