Pietro Nardini (1722-1793) was a violinist and occasional composer. He wrote a few pleasing pieces.
Carl Nielsen is probably the best known composer on the program. But his work would not be described as "pleasing". Very interesting, very innovative, very unusual and very unpredictable could work. He was Danish and lived from 1865-1931. He attended Copenhagen Conservatory and started his career as a violinist, but composing was his calling. He loved Bach and trained well in counterpoint, but loved stretching the harmonic conventions that had been the norm.
Maybe he liked challenges....he married a sculptress who was determined to follow her career path rather than be a wifey, and sometimes left him with the 3 kids to go work at a different site. There were fights and separations but they were together until his death.
His music has become more accepted with the passing of time. The Symphonies are played regularly and the Wind Quintet is standard fare for that combination. The quartets are less known. This one in F Major, Opus 44, is a curious mix. The harmony does strange things and then will settle down and do something whimsical...or leave someone playing a pattern all alone. And there are lush full string moments that are thick and wonderful....you'll see.