Hugh Lloyd-Jones, Blood for the Ghosts: Classical Influences in the Nineteenth and Twentieth Centuries
(1982; rpt. Baltimore: The Johns Hopkins University Press, 1983), p. 158:
Jowett defined a scholar as a man who read Thucydides with his feet on the mantlepiece; by that test he was a scholar, scarcely by any other.
A neatly phrased insult! I haven't been able to locate any such printed definition of a scholar by Benjamin Jowett, who translated Plato and Thucydides. Presumably to pass the test you would need to read the Greek text only, with no help from a dictionary, grammar, or commentary. Thucydides was considered hard to understand even in antiquity. Cicero (Orator
9.30) said, about the speeches in Thucydides, "ipsae illae contiones ita multas habent obscuras abditasque sententias vix ut intellegantur."