Celle (tsĕlˈə) [key], city (1994 pop. 73,670), Lower Saxony, N Germany, on the Aller River. Its manufactures include food products, electronic components, chemicals, and oil-drilling equipment. Wax processing and horse breeding are important locally. Celle was chartered in 1294. Its castle was the residence of the dukes of Lüneburg-Celle, a branch of the house of Braunschweig, from 1378 to 1705. The castle still houses a famous 17th-century Baroque theater. On April 8, 1945, concentration camp prisoners who escaped during an air raid while being transferred to Bergen-Belsen nearby were massacred here.