When, in the third stanza of Catullus' Sapphic poem 11, the tradition preserved by our earliest manuscripts (O, G, R) presented the text

siue trans altas gradietur Alpes
Caesaris uisens monimenta magni
Gallicum Rhenum horribilesque 11
ultimosque Britannos

R2 (Salutati) quickly restored metre to line 12 by transferring ulti– to line 11. At the same time he erased the –que of horribilesque, improving the sense, as we shall see, but leaving the line deficient by one syllable. This was the first recognition of the conflicting demands of sense and scansion in the line, as present in the twentieth as they were in the fourteenth century. Salutati made many such alterations in R, often with an eye to metre, but no manuscript authority lies behind them and we are free to accept or reject his corrections on their own merits. With the first only of these two accepted (as is normal), the lines present us with the notorious crux:

Gallicum Rhenum horribilesque ulti–

mosque Britannos