The most fundamental element of the Gothic style of architecture is the pointed arch, which was likely borrowed from Islamic architecture that would have been seen in Spain at this time. The pointed arch relieved some of the thrust, and therefore, the stress on other structural elements. It then became possible to reduce the size of the columns or piers that supported the arch.
So, rather than having massive, drum-like columns as in the Romanesque churches, the new columns could be more slender. This slimness was repeated in the upper levels of the nave, so that the gallery and clerestory would not seem to overpower the lower arcade. In fact, the column basically continued all the way to the roof, and became part of the vault.