The relationship between a symphony orchestra and a former music director can be a little like an old romance. If the parting was amicable, pleasant reunions are possible.

Of course, Raymond Leppard never really left the Indianapolis Symphony Orchestra. Since stepping down as music director in 2001, he has remained music director laureate and lives in Indianapolis.

However, this weekend's Classical Series program is special, in that it pays a warm 80th birthday tribute to Leppard. The program and his leadership of it reveal a glimpse of his legacy to the orchestra he led for 14 years, and their continuing relationship.

Although Leppard has spoken often of his work to achieve a "classical" sound with the ISO, it was not literally with the music of Mozart or Haydn from the classical era of symphonic music that he is celebrating his birthday. But Leppard did employ some of his trademark conducting tools with a program from the late 1800s and early 1900s -- namely a call for balance, a celebration of orchestral color and a finesse with the sound of the ISO strings.

During the opening "Carnival Overture" by Antonin Dvorak on Friday night at Hilbert Circle Theatre, Leppard quickly revealed his controlled efficiency, with his feet planted firmly, and his body evoking animation without histrionics. The ISO's inner warmth and measured crescendos recalled a Dvorak Symphony No. 7 Leppard led in his last season as music director.

This week, Leppard has also reunited with his longtime colleague, Pascal Rogé, for Maurice Ravel's Piano Concerto in G, a work incorporating the sounds of early jazz. In the Allegramente first movement, everyone brought those fun musical elements to life, from bluesy harmonies, to the wah-wah of a trumpet, to the glissandi (or slides) at the keys and in the orchestra. In the slow second movement, Rogé, hunched over close to the keys, exhibiting considerable calm and elegance.

Throughout the final selection, Edward Elgar's Symphony No. 1, Leppard revived the sweet, shimmering sound he has often achieved with the ISO strings. Generally, they built excitement slowly as themes and long phrases developed, but the performance was not without brilliance.