Task: Question Answering
Input (English): Passage: A third ward was created during Edward I's extension to the Tower, as the narrow enclosure completely surrounded the castle. At the same time a bastion known as Legge's Mount was built at the castle's north-west corner. Brass Mount, the bastion in the north-east corner, was a later addition. The three rectangular towers along the east wall 15 metres (49 ft) apart were dismantled in 1843. Although the bastions have often been ascribed to the Tudor period, there is no evidence to support this; archaeological investigations suggest that Legge's Mount dates from the reign of Edward I. Blocked battlements (also known as crenellations) in the south side of Legge's Mount are the only surviving medieval battlements at the Tower of London (the rest are Victorian replacements). A new 50-metre (160 ft) moat was dug beyond the castle's new limits; it was originally 4.5 metres (15 ft) deeper in the middle than it is today. With the addition of a new curtain wall, the old main entrance to the Tower of London was obscured and made redundant; a new entrance was created in the south-west corner of the external wall circuit. The complex consisted of an inner and an outer gatehouse and a barbican, which became known as the Lion Tower as it was associated with the animals as part of the Royal Menagerie since at least the 1330s. The Lion Tower itself no longer survives. Edward extended the south side of the Tower of London onto land that had previously been submerged by the River Thames. In this wall, he built St Thomas's Tower between 1275 and 1279; later known as Traitors' Gate, it replaced the Bloody Tower as the castle's water-gate. The building is unique in England, and the closest parallel is the now demolished water-gate at the Louvre in Paris. The dock was covered with arrowslits in case of an attack on the castle from the River; there was also a portcullis at the entrance to control who entered. There were luxurious lodgings on the first floor. Edward also moved the Royal Mint into the Tower; its exact location early on is unknown, although it was probably in either the outer ward or the Lion Tower. By 1560, the Mint was located in a building in the outer ward near Salt Tower. Between 1348 and 1355, a second water-gate, Cradle Tower, was added east of St Thomas's Tower for the king's private use. 
Question: What is the first name of the person who built St Thomas's Tower between 1275 and 1279?
Output (English): Edward.