Brand
Contax started as a Zeiss Ikon rangefinder in 1932. The name on the used SLRs you'll find comes from a later alliance between Yashica and Carl Zeiss, which produced the Contax RTS in 1975 and the Contax/Yashica mount it introduced. Zeiss lenses for that mount came in AE and later MM versions, and every Contax and Yashica 35mm SLR shares it, including the 139 Quartz in our catalog. Kyocera bought Yashica in 1983 and kept both names going. Its T-series compacts ran from 1984 to 2002, and the T and T2 have a fixed 38 mm Sonnar. Kyocera also built the G autofocus rangefinders and the N-series SLRs, whose new mount doesn't take C/Y lenses. All Contax camera production ended in 2005.
2 cameras we cover.

Contax · 35mm SLR
Battery neededContax/Yashica (C/Y) mount · 1979–1987
$120–$250 typical ask
44 on eBay

Contax · 35mm compact
Battery neededFixed 38 mm f/2.8 Carl Zeiss T* Sonnar (5 elements in 4 groups) · From 1990–1991
$1,375–$1,875 typical ask
198 on eBay