I am doing a presentation on the rise of Basil I from peasant to Byzantine emperor and i have found a lot of information, but i can not find any info that says whether the act of cutting off the hands off Michael had any significance. I know that the Byzantines would practice mutilation to eliminate a rival, as they could not claim the throne while mutilated, but why bother doing that if you are just going to kill your rival anyway?
Possibly useful text:
http://www.cristoraul.com/PDF-LIBRARY/finlay.pdf
(The linked text is a portion of George Finlay's A History of Greece from the Roman Conquest to the Present Time)
(To find the specific portion you are likely to be interested, CNTRL+F "assassination of michael")
Some of Finlay's text:
Basil soon returned, attended by John of Chaldia, a Persian officer named Apelates, a Bulgarian named Peter, Constantine Toxaras, his own father Bardas, his brother Marines, and his cousin Ayleon. The chamberlain immediately guessed their purpose, and opposed their entry into the chamber. Michael, disturbed by the noise, rose from his drunken sleep, and was attacked by John of Chaldia, who cut off both his hands with a blow of his sabre. The emperor fell on the ground. Basiliskian was slain in the mean time by Apelates. Constantine Toxaras, with the relatives of Basil, guarded the door and the corridor leading to the apartment, lest the officers of the emperor or the servants of Theodora should be alarmed by the noise. The shouts of the chamberlain and the cries of Michael alarmed Basil and those in the chamber, and they rushed into the corridor to secure their retreat. But the tumult of debauchery had been often as loud, and the cries of murder produced no extraordinary sensation where Michael was known to be present. All remaining silent without, some of the conspirators expressed alarm lest Michael should not be mortally wounded. John of Chaldia, the boldest of the assassins, returned to make his work sure. Finding the emperor sitting on the floor uttering bitter lamentations, he plunged his sword into his heart, and then returned to assure Basil that all was finished. The conspirators crossed over to Constantinople...
Finlay indicates that the assassination was done hurriedly, which could mean that the action of cutting off the Emperor's hands was not premeditated.
Alternatively, there is a history of bodily mutilations for political reasons which is well documented and cited here:
http://en.wikipedia.org/wiki/Political_mutilation_in_Byzantine_culture
This means that is possible that the removal of the Emperor's hands was pre-meditated and thus significant. (The significance possibly being that the Emperor was supposed to be physically free from mutilations as an indication of God's favor. If the emperor was physically mutilated he perhaps became in that moment illegitimate).
Since the chroniclers make it seem like it wasn't an act of ritualized mutilation and perhaps more an act of self defense (putting hands up to block a blow). That said, mutilation was a significant part of the Byzantine and roman culture. The Byzantines did commit mutilation much more than the earlier C. Romans because of there deeper belief of Moses's code. See the dumbarton oaks book on religion and the byz. If I remember I wrote this tomorrow I will cite the full title. Lol I love this subreddit