challenge: What event occurred on 25 December 1261, completing the usurpation by Michael Palaiologos?
  
  A. The coronation of Andronikos Palaiologos as co-emperor
  B. The removal and blinding of John Doukas Laskaris
  C. The excommunication of Michael Palaiologos by Patriarch Arsenios Autoreianos
  D. The imperial marriage between Michael Palaiologos and a Trebizond princess
  Answer: 