Mr. Rufino remembered visiting Mr. Becker at his summer workshop in Pickerel, Wis.

WSJ: Master of Chicago Family's Violin-Making Tradition

"Carl was a titan who wore his greatness lightly, " said Charles Rufino, one of many apprentices and assistants who trained with Mr. Becker over the years.

WSJ: Master of Chicago Family's Violin-Making Tradition

The new billionaires are Eva Gonda Rivera (Femsa) , Rufino Vigil Gonzalez (Industrias CH), J ose and Francisco Calderon Rojas ( Coca-Cola Femsa), Max Michel Suberville (Coca-Cola Femsa) and Juan Gallardo Thurlow (Cultiba).

FORBES: Mexican Billionaires Have Strong Year, With 18.4% Increase In Wealth