For example:
The Pope became the anointed leader of kings and emperors, they
becoming his subjects.-or-
The Pope became the anointed leader of kings and emperors, them
becoming his subjects.On one hand, I can see it being the subject pronoun “they” because it appears that “they” is the subject of a form of the verb “becoming” in a phrase. On the other hand, I can see it being the object pronoun “them” with “them” referring appositively back to the object “kings and emperors” as the antecedent and the phrase “becoming his subjects” being an adjectival modifier of “them.”
Answer
The answer is both and will depend on whether you want a more ‘correct’ formal register or a more colloquial one.
They becoming his subjects can be analysed as a nominative absolute phrase.
Usually (…) an absolute phrase (also called a nominative absolute)
is a group of words consisting of a noun or pronoun and a participle
as well as any related modifiers. Absolute phrases do not directly
connect to or modify any specific word in the rest of the sentence;
instead, they modify the entire sentence, adding information. They are
always treated as parenthetical elements and are set off from the rest
of the sentence with a comma or a pair of commas (sometimes by a dash
or pair of dashes). Notice that absolute phrases contain a subject
(which is often modified by a participle), but not a true finite verb.
In this sense, the subject of the phrase will be ‘they’ (in the nominative case).
But in more colloquial English, you will also come across the accusative absolute:
I respected what she said, her being my trusted GP.
Merriam Webster’s first definition of the accusative absolute exemplifies the German language. Wikipedia cites ancient Greek, German and Latin. But the second entry at Merriam Webster is the following:
Accusative absolute
2: a construction in English, especially colloquial English, consisting
of a pronoun in the accusative case joined with a predicate that does
not include a finite verb and otherwise identical with the nominative
absolute (as him being my friend in “him being my friend, I granted
his request”)
Attribution
Source : Link , Question Author : Benjamin Harman , Answer Author : S Conroy