Why did all this happen in the first place? What was it they wanted from Diego? This remains an interesting question and to answer it we have to give up a few assumptions.
First of all, while he certainly performed an ecclesiastic role, Diego Gelmirez was more than just a raised cleric. He was powerful, almost as powerful as the queen, and far more powerful than any single lord of Galicia, the Duke of Traba included, and remember it was he who was the keeper of Alfonso Raimundez, the future king. Diego Gelmirez claimed vast units of property: castles and lands which stretched far outside Galicia. He even owned his own navy: an armada thought to be the first in Spain. Perhaps he was the prototype for that bishop of your chessboard who is second in power only, really, to the queen...
What's more, Diego also had no difficulty with the idea of nepotism. Half his family it seems were under his employ: he used his brothers as ambassadors to foreign courts. One, Gudesindo, he made “villicus” of the town – a position once enjoyed by Diego himself.
One “nephew”, Pedro, was made Prior of the Chapter. (This enigmatic figure of whom we know almost nothing will become a key character in my new book Compostela.) For many, Diego was a hated figure. There seemed no end to what he would do to bring fame and glory to himself, and his cathedral city, but clearly not all of it trickled down to the nobility. If Diego had pretensions to becoming the Spanish "pope", he certainly chose who would likely benefit the most. And who would not...
If all this were not enough, Diego Gelmirez, Bishop of Compostela, turned his nose up at all things Galician; such was too provincial for his way of thinking. No doubt it was to a man who loved French ways in all things. He made key positions available to French clerics; trusted his official records to a Frenchman. And when he made his escape from Santiago in 1117, it was to a French town he fled.
He may have been born Gallego, but Diego Gelmirez had French pretensions. Not surprisingly, it was not liked.