Birthday parties were originated by the Egyptians during the time of the pharaohs. This can also be found in the Bible in the book Genesis when the pharaoh celebrated his birthday. Then after time, the Romans may have popularised these celebrations. However parties were only for men, where the birthday boy would eat a cake made of flour.
It was only after the 12th century that female birthdays were celebrated. Till today, birthdays are being celebrated to celebrate the life of the person and be grateful for it. It is seen to be the most special day for one for it comes only once a year. It makes the person feel extra special and loved.