Crimson Rambler (Rambler) [sport of Rosa multiflora var cathayensis] Much inclined to mildew, but it was a revelation in its time. It has been an important parent.

Moniger: Forcing Crimson Rambler for Easter (1909)

May 13, 2007 (Santa Clara)

May 4, 2004 (Santa Clara) Showing too much mildew.

Eugster & Märki-Fischer: Anthocyanins in Roses (1991)
Pelargonin (62; see Fig. 8) did not appear in roses in color-determining concentrations until 1929. In other garden plants, such as pelargoniums and geraniums, it had been known for years. However, analysis shows that pelargonin is hardly ever formed on its own, but is accompanied in almost all scarlet roses by cyanin (66). 'Gloria Mundi' is one of the very few roses that contains almost pure pelargonin (Fig. 8). Since then, the unexpected appearance of 62 in roses has been traced by many authors (cf. Ref. [62]) to a mutation. Now, however, analyses show that even very old varieties contain significant amounts of 62; examples are R. centfolia muscosa (moss rose, appeared before 1750), 'Königin von Dänemark' (Booth, 1816, alba hybrid?), 'Général Jaqueminot' (Roussel, 1853, hybrid perpetual), 'Crimson Rambler' (Japan, pre 1890, multiflora hybrid), and 'Soleil d'Or'. In contrast to the views of Refs., we also found pelargonin in botanical roses, such as R. pendulina, R. willmottiae, R. rugosa, R. pomifera, and R. gallica versicolor.
....The mysterious 'Crimson Rambler' and 'Königin von Dänemark' also contain unexpectedly high levels of peonin, which throws new light on their unknown pedigrees.

Aristocrats of the Garden pp. 8-9. (1917)
Ernest Wilson
In 1878, Prof. R. Smith sent from Japan to Mr. Jenner in England a Rose which the recipient named The Engineer in compliment to the profession of its donor. In course of time this Rose came into possession of a nurseryman named Gilbert who exhibited some cut flowers of it under the above name in 1890, and received an Award of Merit from the Royal Horticultural Society. Soon afterward Messrs. Chas. Turner, of Slough, purchased the stock and changed the name to Crimson Rambler. This Rose is generally assumed to be a hybrid between Rosa multiflora and some China Monthly Rose, but to me this view is untenable. I do not think it has any China Monthly blood in it at all. It has long been cultivated in China and I consider that, like the Seven Sisters Rose, it is a sport from the common, wild pink-flowered China Rambler (R. multiflora, var. cathayensis). These various Chinese Roses were introduced from Chinese gardens where they have been cultivated from time immemorial and their wild prototypes were not discovered, much less introduced, until comparatively recently.
    The true Rambler Rose (R. multiflora) is a native of Japan and has single white flowers in large panicles. This was sent to Lyons, France, from Japan in 1862, by Monsieur Coignet, an engineer. The pink-flowered Chinese variety has only just been dignified by a distinctive name.