Rome

The other name for cos lettuce is simply Roman.

French romaine means Roman, said to record the lettuce reaching France from papal Avignon. English took the French name for the same plant it already called cos.

A facial profile is named for a city's portrait busts.

English took the profile of Roman portrait sculpture as the type, and the phrase has described the shape ever since.

The Roman road network really did radiate from one gilded marker in the Forum.

Imperial roads were reckoned from the Milliarium Aureum, the golden milestone Augustus set in the Forum as the point where every road was considered to begin. The proverb is medieval rather than Roman; Latin versions circulate from the twelfth century before English picks it up.

The fiddle would not be invented for another fourteen centuries.

Roman writers reported that Nero sang about the fall of Troy during the fire of AD 64, and later retellings handed him a fiddle instead; bowed instruments reached Europe much later, and the violin is a 16th-century creation. Tacitus also places Nero outside the city when the fire started, which spoils the picture further.

The proverb about Rome reached English through medieval France.

It circulates in twelfth-century French collections as "Rome ne fut pas faite toute en un jour" and entered English proverb books in the 1500s, notably John Heywood's. Rome is standing in for the largest thing anyone could picture building, not making a claim about actual construction schedules.

The advice started as a bishop's ruling on which day to fast.

Ambrose of Milan reportedly told Augustine to fast on Saturday while in Rome and not to in Milan, following each church's local custom, and the anecdote hardened into a proverb. English versions appear by the sixteenth century, by which point the fasting question had dropped out entirely.