... Step by step Kaloyan was preparing for the victory that was finally won on 14 April 1205 near Adrianople. The Bulgarian shield clashed with the amour of the Latin knights, headed by Emperor Baldwin I Military historians have noted Kaloyan's skill in laying an ambush and, for the first time in Bulgarian history, the use ofreconnaissance in fight. They emphasize the excellent training of the Bulgarian troops and the perfect timing of the attack. The Bulgarian infantry and the Kumanian light cavalry routed the heavily armored knights, who had previously been considered invincible. "The cream of Latin chivalry was killed in that battle," wrote Robert de Claris. The emperor himself was captured and taken to Turnovo.
The battle of Adrianople, which revealed Kaloyan's exceptional talent as a military commander, echoed throughout Europe. The Latin empire was delivered a heavy blow and was to collapse several years later. In Rome the Pope had to give up his hopes of gaining control over the Eastern Orthodox Church. But it was not only fame Kaloyan fought for at Adrianople. His mind was focused on Bulgaria's survival next to the mighty Latin empire. ..
The info was taken from the site Bulgaria.com , Rulers of Bulgaria section