First of all, there is some discrepancy concerning today’s date, but part of that is because we are talking about an event that happened in B.C. (I will continue to use B.C. and A.D. instead of the new-fangled B.C.E. and A.C.E.). On this date (or on July 12) in 100 B.C., Julius Caesar was born. His full name was Gaius Julius Caesar, and from 47 to 44 B.C., he was dictator of Rome. I am not going to take the time to go into the absolute ruler that he was and all the details surrounding this. You can research that yourself (check out the links at the end of the post). During his rule, he brought about a lot of positive changes, but a group of his senators who did not agree with his views (led by Cassius and Brutus) assassinated him on March 15, 44 B.C. (the Ides of March). The main issue appeared to be that Caesar made his dictatorship for life, rather than temporary as it had traditionally been, earlier that year.
For more info:
http://www.vroma.org/~bmcmanus/caesar.html
http://en.wikipedia.org/wiki/Julius_caesar
http://www.biography.com/people/julius-caesar-9192504
http://www.bbc.co.uk/history/historic_figures/caesar_julius.shtml
http://www.roman-empire.net/republic/caesar-index.html
http://www.famousbirthdays.com/people/julius-caesar.html