Gibbs is new to the SCA, but had done some other medieval-themed activities under that name and wanted to find a registrable equivalent that fit with their late-period English persona and paid homage to a grandfather named Morris.
Gibbs appears to have originally been a pet name or diminutive version of “Gilbert” before becoming established as a distinct name of its own. Morris seems to be an Anglicized version of the French “Maurice.” Both names came to England with the Norman invasion.
We spent some time looking at alternate spellings: Gibbs and Gibbes are both historically attested as English or Lowland Scots names, as are Morris, Moryis, Moryss, and Morrys.
When my first search only turned up documentation of Gibbs as a surname, we thought we might use Morris as a first name, perhaps with the spelling “Moryis Gibbs,” but then reconsidered when multiple people said this made them think of Maurice Gibb, a singer with the Bee Gees.
After turning up some additional sources, Gibbs Moryss emerged as the favorite.
Gibbs is a sixteenth-century English male given name, sometimes spelled “Gibbes.”
“Gibbs Wills” was the name of a man married on October 9, 1619 in Kent, England (Family Search, batch number M01596-5).
“Gibbs Hicksome” was the name of a boy christened on January 18, 1628 in Kent, England (Family Search, batch number C03656-1).
Moryss is a sixteenth-century English surname, sometimes spelled “Morrys.”
“John Moryss” was the name of a boy christened on February 13, 1562 in Langton by Wragby, Lincoln, England (Family Search, batch number C02972-2).
“John Moryss” was also the name of a boy christened on March 26, 1629 in Hereford, England (Family Search, batch number C13862-1).
[Update:] Gibbs’s name was accepted on the August 2018 LoAR, published in October, with the following note indicating that while this version of the name was registrable as English, there was a variation which was more Scottish:
The submitter requested authenticity for 16th century “Lowland Scots-English.” This name does not meet that request. The spelling Moryss is found in English; in Scots, it can be interpolated as a plausible variant spelling from period examples. However, we have no examples of Gibbs as a Scottish given name. In the Letter of Intent, it was documented as a gray-period English surname used as a given name. Thus, while this name can be registered, it is not authentic for the requested time and place.
The submitter may be interested to know that Gib_ Moryss appears to be authentic for circa 1500 in Scotland. If the submitter prefers this form, he may make a request for reconsideration.