John of Brienne had filled his thankless office but two years when the capital was menaced by the allied forces of the Emperor of Nicea and the King of Bulgaria. It was a critical moment. The Latin army was much reduced by desertion, and it is said Brienne had less than two hundred knights and four hundred footmen to oppose an army of many tens of thousands. But the brave old Emperor--he was eighty years of age--put himself at the head of his little band and sallied forth to meet the host. An impetuous charge scattered them like chaff. The Venetians, too, were not slack. An urgent message had been sent for help, and a fleet of twenty galleys was hastily sent to Constantinople, which swooped down on the Greek fleet at the entrance to the Dardanelles. The whole _Armata_ and transports were destroyed or taken, and the Venetian admirals made triumphant entry into Constantinople to receive the felicitations of the Emperor. Two years later the Greeks were again foiled by the irresistible onslaught of the Venetian and Latin fleets. At the death of John of Brienne financial ruin was impending and a strange expedient was adopted to raise a loan. Of the sanctuary spoils at the taking of Constantinople, the crown of thorns had been appointed to the emperor. It was now brought forth with the lance of the passion and mortgaged to the Venetian Bailo of Constantinople, Alberto Morosini, for the loan of 14,000 _perperi_ subscribed by the leading merchants. The bill fell due: the money was not forthcoming and the security was legally forfeited. But a third party was found in the person of a rich Venetian banker, who, towards the end of the year 1237, advanced the sum for a month to give breathing time. If the payment was again deferred the lender might remove the relic to Venice for a period of four months, which being expired the mortgagee was empowered to foreclose. Meanwhile the saintly king, Louis IX. of France, had heard of the transaction and was much scandalised. He sent two Dominicans to Constantinople to redeem the pledge and secure the precious relic for Paris. It was, however, already on its way to Venice when the two black friars reached the capital of the Empire. The good ship that was freighted with the thorns arrived at Venice on the 4th of September 1238. Hastily the envoys retraced their steps and sought an audience of Tiepolo, who straightway led them to St Mark’s and showed them the sacred treasure. They then went to the banker and offered the money to redeem the pledge. It was handed to the friars who returned joyfully to Paris. King Louis, barefoot and in his shirt, took part in the solemn procession that accompanied the relic through the streets of Paris and the Sainte Chapelle, the richest gem of Gothic architecture in North Europe, was built to receive it.