The XML dialect called AIML was developed by Richard Wallace and a worldwide free software community between 1995 and 2002. AIML formed the basis for what was initially a highly extended Eliza called "A.L.I.C.E.." ("Artificial Linguistic Internet Computer Entity"), which won the annual Loebner Prize Competition in Artificial Intelligence three times, and was also the Chatterbox Challenge Champion in 2004.
Categories in AIML form the fundamental unit of knowledge. A category consists of at least two further elements: the pattern and template elements.
A pattern is a string of characters intended to match one or more user inputs. A literal pattern like WHAT IS YOUR NAME will match only one input, ignoring case: "what is your name". But patterns may also contain wildcards, which match one or more words. A pattern like WHAT IS YOUR * will match an infinite number of inputs, including "what is your name", "what is your shoe size", "what is your purpose in life", etc.