C carnosus was widely available from alpine nurseries; Backhouse of York from 1895, Six Hills Nursery from 1914, Ingwersens and Gavin Jones from 1926 and Stuart Boothman from 1938.  It was available as T. erectus from J. Robinson & Son from 1931 and also from Reginald Kaye, who later listed it as T. carnosus.  It was available from Alan Smith in 1955 as T. carnosus with T. erectus as a synonym and from Blooms of Bressingham, also in 1955, as T. erectus with T. carnosus as a synonym.  It was first listed in the 1990 Plant Finder as T. vulgaris 'Erectus', but the nurseries listed were offering T. carnosus.  Comparison of plants shows that they are identical, the inflorescence is not characteristic of T. vulgaris and the bracts are ovate, not ovate-lanceolate like the leaves, rather than similar to the leaves in T. vulgaris.

Clarence Elliott of Six Hills Nursery, Stevenage, introduced a deep crimson flowered thyme in 1914 as T. serpyllum coccineus majus, later known as T. serpyllum coccineus 'Major' and T. serpyllum 'Coccineus Major'.

When the Thymus Coccineus Group was created in 2001 it was decided not to include this cultivar in the Group, as although the flowers are deep crimson, the growth pattern is more like that of T. pulegioides.  In 2003 I renamed it T. 'Coccineus Major'; first published in Plant Heritage, Spring 2003.  The Latin form of the epithet Coccineus Major is permissible as its earliest known reference predates 1959.