Proofreading english text
You can correct the translation errors in the English text???
Thanks in advance
Las Torres estan situadas en la desembocadura del río, pero hoy estan en ruinas. La fecha de construcción es motivo de debate entre algunos historiadores. Pero es anterior a la llegada de los romanos hace 2000 años, pues Pomponio Mela menciona la existencia de las mismas en una de sus obras. Esta fortaleza se utilizó durante siglos para contener las incursiones de vikingos, normandos y sarracenos, que llegando por mar, intentaban remontar el río para llegar a X y saquearla. A cada lado del río los defensores disponian de una manada de bueyes que cuando aparecia un barco sospechoso tiraban de unas grandes cadenas para impedir que los barcos remontasen el rio.
Translation: The towers are located at the mouth of the river, but today are in ruins. The date of construction is a matter of debate among some historians. But before the arrival of the Romans 2000 years ago, as Pomponius Mela mentions the existence of the same in one of his works. This fort was used for centuries to prevent the incursions of Vikings, Normans and Saracens, who arrive by sea, up the river trying to get to "X" and plunder. On each side of the river the defenders possessed a herd of oxen that when a suspect ship appeared pulled. a some big chains to prevent large boats go up the river.
2 Answers
Las Torres están situadas en la desembocadura del río, pero hoy están en ruinas. La fecha de construcción es motivo de debate entre algunos historiadores. Pero es anterior a la llegada de los romanos hace 2000 años, pues Pomponio Mela menciona la existencia de las mismas en una de sus obras. Esta fortaleza se utilizó durante siglos para contener las incursiones de vikingos, normandos y sarracenos, que llegando por mar, intentaban remontar el río para llegar a X y saquearla. A cada lado del río los defensores disponian de una manada de bueyes que cuando aparecia un barco sospechoso tiraban de unas grandes cadenas para impedir que los barcos remontasen el rio.
Translation: "The towers are located at the mouth of the river, but today they are in ruins. The date of construction is a matter for debate among some historians, but took place before the arrival of the Romans 2000 years ago, as Pomponius Mela mentions the existence of the same in one of his works. This fort was used for centuries to prevent the incursions of Vikings, Normans and Saracens, who arrived by sea, and navigated up the river trying to get to "X" and plunder. (or you could say, to get to a certain point to plunder their property) On each side of the river the defenders possessed a herd of oxen, so that when a suspect ship appeared, they would pull some big chains to prevent large boats going up the river".
Excellent work ! You have done very well and made only a few mistakes in writing a complicated historical account! I hope this helps you 
I have made some corrections to the English in your sentences which I have highlighted using bold text. I have also suggested an alternative way to write the end of one of your sentences which I have placed in parenthesis (brackets) If you choose too use my corrected text you will need to add some Spanish words and phrases that I have added in so that both texts match!
I am correcting based on English used in England! These days it seems that people in the U.S.A. generally seem to accept starting sentences with conjunctions such as But or And in their literature but I was taught at school, college and University that this is not good practice, by that I mean, not an acceptable way to write good English! I have only added quotation marks to your text to enable you and other people to easily distinguish between your text and my comments at the end!
Great essay! Here are some suggestions:
The towers are located at the mouth of the river, but today they are in ruins. The date of construction is a matter of debate among some historians. But it was before the arrival of the Romans 2000 years ago, as Pomponius Mela mentions their existence in one of his works. This fort was used for centuries to prevent the incursions of Vikings, Normans and Saracens, who, arriving by sea, tried to go up the river to get to "X" and plunder it. On each side of the river the defenders possessed a herd of oxen that when a suspect ship appeared pulled on some big chains to prevent large boats from going up the river.
