1999 May 5th
W3C, in co-operation with the WAI initiative, issued the first recommendation for a set of Web Content Accessibility Guidelines (WCAG 1.0). The WCAG 1.0 consists of 14 general rules that represent the basic principles of accessibility. In addition to these rules, WCAG 1.0 also includes checkpoints that explain given problems. Each checkpoint is assigned a priority on the following scale: the highest (priority 1), medium (priority 2) or lower (priority 3).