At the end of Tupac's life he changed his name to Makaveli.
The name Makaveli comes from Nicolo Machiavelli a 14th century Italian philosopher, statesman, writer and political theorist.
Machiavelli was born in Florence on May 3, 1469. In 1532 he wrote his masterpiece : The Prince
The Prince whose main theme was that all means may be used in order to maintain authority, was condemned by the pope Clement VIII
His first book was published in 1782. 

Machiavelli faked his dead in order to evade one's enemies. Tupac was interested in this theory and changed his name in Makaveli, and also his album Makaveli - The 7th Day Theory.

Tupac read the book The Prince - Nicolo Machiavelli. You can order the book in every good bookshop.
There are also a couple of online versions on the net if you are searching.

The Prince 
by Niccolo Machiavelli, Daniel Donno (Introduction) 

Paperback - 147 pages Reissue edition (September 1, 1984) 
Bantam Classic and Loveswept; ISBN: 0553212788
Other Editions: Hardcover, Audio Cassette