The Obelisk was brought to Rome from Heliopolis, Egypt by Emperor Caligula in 37 BC. It was brought over in a ship that was filled with lentils to prevent from damaging the stone. Pharaoh Mencares ordered the construction of this obelisk originally in 1835 BC in honor of the sun god. It's original location in Rome was on a spot south of the basilica, close to the present day sacristy and it witnessed many saints martyrs, one of which was St. Peter's.
Relocation to the Front of St. Peter's
Under the order of Pope Sixtus V, Domenico Fontana took on the responsibility of relocating this 327 ton monolith that was 83 feet long in 1586. Nobody wanted to take on the responsibility of relocating the obelisk because of the death penalty being sentences if it was dropped or broken. The death penaly was also being issued to anyone who broke the silenced required for such great focus. The move of the obelisk required the help of 900 men and 72 horses and they did this using hemp ropes and iron bars. According to myth, a sailor from Genoa shouted "throw water on the ropes" as he saw that the ropes were about to give. The ropes shrunk back to normal and the task was completed without this sailor being punished for breaking the silence.
In the times of the Ancient Egyptians, obelisks were placed in pairs at the entrances of temples. It symbolized their belief in the sun god Ra. For the Egyptians, the sun was the giver of life, therefore the importance of honoring him in an important way. The Romans took great influence from these obelisks so as a sign of their overwhelming power, they took many of the Egyptian obelisks and relocated them to Rome. Their are now more than twice amount of obelisks in Rome than there are in Egypt. The question is raised that if the meaning of the obelisk to an Egyptian is to honor the sun god, why would they want to locate it in the embracing arms of St. Peter's square? Pope Benedict XVI more recently gave an explanation that the sundial is meant to remind the faithful to make time to pray through out the day.