The IS was originally sold under the Toyota Altezza nameplate in Japan from 1998 (the word Altezza is Italian for "highness") until the introduction of the Lexus brand and the second-generation Lexus IS design in 2006. The IS was introduced as an entry-level sport model positioned below the ES in the Lexus lineup. The Altezza name is still used at times to refer to chromed car taillights like those fitted to the first-generation model, known as "Altezza lights"
The first-generation Altezza (codename XE10) was launched in Japan in October 1998, while the Lexus IS 200 (GXE10) made its debut in Europe in 1999 and in North America as the IS 300 (JCE10) in 2000. The first-generation, inline-6-powered IS featured sedan and wagon variants. The second-generation IS (codename XE20) was launched globally in 2005 with V6-powered IS 250 (GSE20) and IS 350 (GSE21) sedan models, followed by a high-performance V8 sedan version, the IS F, in 2007, and hardtop convertible versions, the IS 250 C and IS 350 C, in 2008. The third-generation Lexus IS premiered in January 2013 and includes the V6-powered IS 350 and IS 250, hybrid IS 300h and performance-tuned F Sport variants. The IS designation stands for Intelligent Sport.
Wikipedia: Lexus IS