The Medici Tombs was the first Michelanglo Project to be
actually built. The tomb was originally intended for
Michelangelo's patrons, Pope Leo and Cardinal Guilano's fathers: Lorenzo the Magnificent
and his Brother Guilano and for their young relatives Duke Guilano
and Duke Lorenzo. But only the tombs for the young relatives
were fininished. The older men rest in a "cassone", or burial chest
opposite the altar.
The rise of Alessandro to power caused Michealangelo to flee Florence in 1534, leaving the tombs unfinished. Assandro was murdered in 1537 that provided a reason for assembling the tomb. The body of despot Alessandro lies on top of the remains of Lorenzo.
As you can see the portrait paintings don't look anything like the the statues. When this was pointed out to Michelangelo he said: (paraphrasing) "500 years from now the world could care less what they look like ..just that the tomb was made by me.