Historian Sheilagh Ogilvie challenges the view that training by European craft guilds from 1560 to 1760 was necessary. Her main evidence, however, is based only on female employment in one guild. Like most other guilds, the Wildberg weaver's guild banned women from becoming masters, however, it exempted master's widow. Indeed, widows accounted for 14 percent of all masters. Ogilvie claims that these "untrained" widow prove "the irrelevance of training." But Wildberg master-widows were not untrained for, as Ogilvie notes elsewhere, wives and children worked with masters, their training may have been informal, but it existed nevertheless. At least 80 percent of widows were married to masters for longer than the standard six-year apprenticeship, an unknown proportion of the remainder had grown up in weaving families.