A quotation by Eduard Kummer

It is greatly to be lamented that this virtue of the real integers that they can be decomposed into prime factors which are always the same for a given integer does not belong to the complex integers [of arbitrary cyclotomic number fields], for were this the case, the entire theory, which is still labouring under many difficulties, could easily be resolved and brought to a conclusion.
De numeris complexis, qui radicibus unitatis et numeris integris realibus constant 1847