The union effected was "a sham and a political gambit", a fiction maintained by the emperor to prevent westerners from recovering the city of Constantinople, which they had lost just over a decade before, in 1261. It was fiercely opposed by clergy and people and never put into effect, in spite of a sustained campaign by Patriarch John XI of Constantinople (John Bekkos), a convert to the cause of union, to defend the union intellectually, and vigorous and brutal repression of opponents by Michael. In 1278 Pope Nicholas III, learning of the fictitious character of Greek conformity, sent legates to Constantinople, demanding the personal submission of every Orthodox cleric and adoption of the "Filioque", as already the Greek delegates at Lyon had been required to recite the Creed with the inclusion of "Filioque" and to repeat it two more times. Emperor Michael's attempts to resolve the schism ended when Pope Martin IV, seeing that the union was only a sham, excommunicated Michael VIII 1281 in support of Charles of Anjou's attempts to mount a new campaign to retake the Eastern Roman provinces lost to Michael. Michael VIII's son and successor Andronicus II repudiated the union, and Bekkos was forced to abdicate, being eventually exiled and imprisoned until his death in 1297.