The Venturi were known as an old and honorable race. However, by the late 23rd century, their sun showed signs of instability, causing many disasters on their homeworld. The Federation began relief efforts, but most of the Venturi refused to relocate. Some Venturi saw the Federation's assistance as demeaning, and turned to piracy and marauding.
By the 24th century, the Venturi had become members of the Federation, though splinter sects were still in existence and frequently plagued shipping lines. (Star Trek: Pendragon)