What's the difference between i.e. and e.g.?
early 13c., "eve of a religious festival" (an occasion for devotional watching or observance), from Anglo-French and Old French vigile, from Latin vigilia "watch, watchfulness," from vigil "watchful, awake," from PIE *wog-/*weg- "be lively or active, be strong" (cf. Latin vigere "be lively, thrive," velox "fast, lively," vegere "to enliven;" Sanskrit vaja- "strength, speed;" Old English wacan "to wake up, arise," wacian "to be awake;" Old High German wahta "watch, vigil"). Meaning "watch kept on a festival eve" is from late 14c.; that of "occasion of keeping awake for some purpose" is recorded from 1711.
watch or vigil held over the body of a dead person before burial and sometimes accompanied by festivity; also, in England, a vigil kept in commemoration of the dedication of the parish church. The latter type of wake consisted of an all-night service of prayer and meditation in the church. These services, officially termed Vigiliae by the church, appear to have existed from the earliest days of Anglo-Saxon Christianity. Each parish kept the morrow of its vigil as a holiday. Wakes soon degenerated into fairs; people from neighbouring parishes journeyed over to join in the merrymaking, and the revelry and drunkenness became a scandal. The days usually chosen for church dedications being Sundays and saints' days, the abuse seemed all the more scandalous. In 1445 Henry VI attempted to suppress markets and fairs on Sundays and holy days