Company History In the 1870s, electricity was more a sideshow attraction than a critical necessity. Electric arc lamps—a Barnum and Bailey circus attraction—were uncomfortably bright and hot, making the lamps not only impractical for indoor use but also expensive to operate. Not until October 21, 1879, when New Yorker Thomas A. Edison invented the first successful incandescent lamp, did electric lighting start to become widespread and economical. Perhaps the most momentous event in the history of two Illinois and Missouri energy companies came more than 100 years later. In December 1997, Union Electric and CIPSCO Incorporated, parent of Central Illinois Public Service Company, merged, creating Ameren Corporation and its principal operating companies—AmerenUE and AmerenCIPS. In 2003, Ameren Corporation grew with the acquisition of CILCORP Inc., parent company of Central Illinois Light Company (CILCO). The following year, the company grew again when it acquired Illinois Power Company, now known as AmerenIP. Together, these companies can rightly claim more than a century of excellence in delivering low-cost, reliable service at rates that are well below the national average. In fact, AmerenUE’s 1.2 million electric customers in the St. Louis area currently enjoy the second lowest rates of any metropolitan region in the nation, while Ameren’s rates are nearly 40 percent below the national average. Together, Ameren, its operating companies and its subsidiaries are proud of their tradition of service—and proud to serve their 2.3 million electric and 900,000 natural gas customers in Missouri and Illinois.

Thomas A. Edison presents the incandescent lamp.