Codenamed P5, the Intel Pentium was released by Intel on March 22, 1993 as a replacement to the 80486 processor and originally sold for $878.00. The name comes from the Greek word for "five" and is used because it's the fifth processor in the 80x86 line. It would have been called the 80586 had a US court not ruled that you cannot trademark a number. The Intel processors were available between speeds of 60MHz and 300MHz, had a 64-bit databus, and had an additional 1.9 million transistors when compared to the 80486DX (3.1 million). Below is a graphic illustration of the Pentium processor.
The original Intel Pentium was released using a 273-pin PGA form factor and ran on 5v power. Intel later announced the release of a second-generation introduced March 7, 1994 included new processors from 75, 90, 100, 120, 133, 150, 166, and 200 MHz. The processors used 296-pin SPGA form factor that is physically incompatible with the first generation versions. The third-generation of Pentium processors, code named P55C, were introduced January 1997, which incorporated the new technology MMX. The Pentium MMX processors were available 166, 200, 233 MHz, and 266 MHz mobile version.