The mandolin belongs to the same family as the lute, has the same shape, but is considerably smaller, and it was transformed as time went by.
The ancient mandolin, called mandolino, was quite similar to the lute, and its body also had a round back and a flat front. It had four double strings, but there was no steep inclination in the arm's extremity.
Mandolino, built by Vincenzo Vinaccia, 1775
As the years went by, the mandolin was transformed, and currently still has four double strings and a pear or waterdrop shape, but both the front and the back became flat. Although having been used already in classical music, it is also traditionally used in the accompaniment of choro and samba.
The mandolin was very widespread in Rio de Janeiro's popular music, specially in choro, by the carioca musician Jacob do Bandolim (1918-1969), who was the most important and popular brazilian mandolinist.
Jacob and his mandolin