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. Union Electric and CIPSCO Incorporated, parent of Central Illinois Public Service Company, merged in December 1997, creating Ameren Corporation. Ameren is the parent of Union Electric -- now AmerenUE -- and Central Illinois Public Service company -- now AmerenCIPS. The two companies can rightly claim a century of excellence in delivering low-cost, reliable service at rates that are well below the national average. What follows is the story of how these two companies became strong, successful enterprises and grew with the utility industry.