English and Irish pet name for Mary, derived from the earlier pet name Mally.
A correspondent [GJ] reports that, in the early 16th century, the female name Male was used in the Kirk Session records of St Andrews, Scotland [transcribed by the Scottish History Society]. We presume this to be an early phonetic spelling variant of Mally/Molly.
A private communication [AB] suggests May as a pet name for Marjory, Margery, Marjorie and Molly. This occurs in some official records and it might be well to consider May when searching for Molly as Soundex searching will not return this variant.
The early use of Polly - derived from Molly - as a widely-used pet name for Mary is supported by MB who sent us a transcription of a letter dated 1796 in North Carolina, USA. In the letter a child named Mary is frequently referred to as "Polly".
A Scottish correspondent [MC2] reports cases where either Molly or Polly was used as a pet name for Mary, but was sometimes developed to Dolly, although this is very unusual.
Peggy developed from Meggy (pet name for Margaret) at the same time as other "M-" to "P-"conversions, such as Molly to Polly. The reason for this consonant shift is unclear.