This is a recurring series by Mistress Alys Mackyntoich on whether certain names currently can be documented to period based on existing evidence.. There are a lot of names that people think are medieval, but actually aren’t, and others which people think are modern, but in fact are found in the SCA’s period. If you would like to suggest a name, send an email to the Gazette.
The male name Ian, pronounced like “Ee-an,” is popularly thought to be a period Irish or Scottish name. In fact, Ian is not found in period Gaelic, Scots or Anglicized Irish. Although there are a few examples of the spelling Ian in gray-period English (that’s the period between 1600 and 1650), that name was more likely pronounced like “Yan” than like the modern “Ee-an.”
There are a few names in Gaelic that sound like the modern “ee-an” but, because of the weirdness that is Gaelic spelling, these names don’t look anything like Ian. The Gaelic name Áedán is actually pronounced something like “ee-an.” In addition, the Gaelic name Áedegan is pronounced like “eye-an.” 
 Ian Moore; Male; Marriage; 27 November 1608; Leconfield, Yorkshire, England; Batch: M060801 (https://familysearch.org/ark:/61903/1:1:NVTY-232).
 Ó Corrain, Donnchadh & Maguire, Fidelma. Irish Names. (Lilliput Press, 1990) at 13.
 Id. at 14.