Passage down the nave: 6
Now you have a clear view into the lateral spread of the cathedral: the north transept: visual accessibility is enhanced by the wider arcade bay adjacent to the crossing. This enlarged bay breaks the regularity of the nave system creating the effect of a spatial transformation. The plan results from the presence of a great square at the center of the cathedral embracing the crossing and the four adjacent bays (see plan below)
You can see into the chapel to the east of the north transept: originally dedicated to Saint Peter, it was, in the 18th century, converted to the chapel of John Baptist and the famous head of the saint, once housed in an upstairs chapel to the north of the choir, was relocated here. Look up into the east side of the north transept arm: you can see that the triforium which, in the nave, was dark is now lit by windows: the same arrangement continues into the choir. In other words, the first major architectural transformation we have seen in our passage down the nave occurs in the upper eastern side of the transept arms, the work of young Renaud de Cormont who replaced his father Thomas circa 1250.