Here is a part of the article, although the author does not hide his antipathy towards the Bulgarians.

The europeans attacked to the sea walls on 8th April 1204. The ships drew near to the city, and a fierce battle began in more than a hundred places. The crusaders were repulsed in that assault, and those who had landed from the galleys were driven back. After the defeat, the Doge of Venice and the other barons were assembled in a church on the other side of the straits and discussed. The Venetians insisted that they should repeat the attacks to the same place, but this time the ships should be bound together in order to reach the high towers. The preparations lasted some days and the final assault was repeated on 13th April 1204. The Greeks defended the towers with success, but suddenly the wind changed and blew from the north. Two ships that were bound together, the Pilgrim and the Paradise, approached so near to a tower, that the ladder of the first vessel joined on to the tower. Immediately a Venetian, and two French knights, whose name was Andrew of Durboise and John Choisy, entered into the tower. This was the beginning of the end. The tower was taken and many other crusaders raised their ladders and conquered many other towers. In vain the emperor Alexius Mourzuphlus tried to encourage his soldiers to counterattack. They fled and Alexius ran to the castle of Bucoleon. He took with him Eufrosine and her daughter Eudokia and left the Byzantine capital through the Golden Gate. The Latins set again fire to the city.
And the city began to take fire, and to burn very direfully; and it burned all that night and all the next day, till vesper-time. And this was the third fire there had been in Constantinople since the Franks arrived in the land; and more houses had been burned in the city than there are houses in any three of the greatest cities in the kingdom of France.
When Alexius V left the City, Constantine Lascaris one of the city's leading defenders, was proclaimed emperor in the Cathedral of St. Sophia. He tried with his brother Theodoros Lascaris to drive the Varagkoi (Vikings mercenaries) against the invaders, but again the attempt had no result and the two brothers fled the city. In Nicaea, Theodoros Lascaris would later create a new Byzantine state, the Empire of Nicaea. One of his successors Michael VIII Paleologus in 1261, would liberate the Greek capital.
The richest city of the world was at the mercy of the Europeans. The barbarians did horrible things that are beyond imagination. They tortured and massacred a large part of the population, destroyed churches, palaces, monasteries and even sculptures made by Phedias and Praxiteles, stole thousands of priceless icons, relics and other things, raped young girls and boys...
https://www.agiasofia.com/emperors/fall1204.html
https://en.wikipedia.org/wiki/Sack_of_C ... ple_(1204)
https://www.ancient.eu/article/1188/120 ... antinople/