It remains only to speak of the person who should have been to Rome what the national king was to the cities of France, or England, or Germany, that is to say, of the Emperor. As has been said already, his power was a mere chimera, chiefly important as furnishing a pretext to the Colonna and other Ghibeline chieftains for their opposition to the papal party. Even his abstract rights were matter of controversy. The Popes, whose predecessors had been content to govern as the lieutenants of Charles and Otto, now maintained that Rome as a spiritual city could not be subject to any temporal jurisdiction, and that she was therefore no part of the Roman Empire, though at the same time its capital. Not only, it was urged, had Constantine yielded up Rome to Sylvester and his successors, Lothar the Saxon had at his coronation formally renounced his sovereignty by doing homage to the pontiff and receiving the crown as his vassal. The Popes felt then as they feel now, that their dignity and influence would suffer if they should even appear to admit in their place of residence the jurisdiction of a civil potentate, and although they could not secure their own authority, they were at least able to exclude any other. Hence it was that they were so uneasy whenever an Emperor came to them to be crowned, that they raised up difficulties in his path, and endeavoured to be rid of him as soon as possible. And here something must be said of the programme, as one may call it, of these imperial visits to Rome, and of the marks of their presence which the Germans left behind them, remembering always that after the time of Frederick the Second it was rather the exception than the rule for an Emperor to be crowned in his capital at all. [Sidenote: Their approach.]