The Lawrence Motet Singers are in the middle of a busy summer season. The group, best known for its performance of Renaissance music, is concentrating on music by Russian composers from the 18th through 20th centuries this summer.

The group is singing at the 5:30 p.m. Mass today at St. John’s the Evangelist Church. They’ll also perform at 10:30 a.m. Sunday at Trinity Episcopal Church. Performances will include compositions by Alexander Arkhangelski, Grigory Lvovsky, Dimitry Bortniansky, Alexander Kastalsky, Dimitry Soloviev and A.F. Lvov.