First of all, Rus. "патрикий" = Lat. "patricius" = Gr. "patrikios" is NOT A NAME, but A TITLE in Late Roman and Byzantine times, first reintroduced by Constantine the Great to revive the Ancient Roman title ( https://en.wikipedia.org/wiki/Patrikios ). Wikipedia has a category page for the Byzantine patricii that have their own article ( https://en.wikipedia.org/wiki/Category:Patricii ).

Second of all, I believe the "Кир" you are looking for is Cyrus of Panopolis ( https://en.wikipedia.org/wiki/Cyrus_of_Panopolis ). Everything fits:
- he lived in the right century;
- he "erected a church to the Theotokos in a district that later bore his name". So (a) the church is right (Theotokos Kyriotissa) and (b) he had a district named after him in later times, just like the book says (in the quote about Роман Сладкопевец).

So, all in all, it's :
- either Cyrus the Patrician - on the model of "Peter the Patrician" ( https://en.wikipedia.org/wiki/Peter_the_Patrician ) who is "Пётр Патрикий" in Russian;
- or Cyrus of Panopolis - if you want to use the name under which he is apparently better known in English (which is, of course, not always on the same pattern as the name under which a person is best known in Russian).

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Note added at 34 mins (2015-08-15 23:15:24 GMT)
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PS. By the way, the title "патрикий" is mentioned several times on earlier pages of the book (as well as, of course, later on)...

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Note added at 10 hrs (2015-08-16 09:12:02 GMT)
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PPS. What I meant in my PS last night wasn't that you should have known it from before!.. I am sorry if that sounded rude, it was like 4 am when I was writing. :) What I meant is that you might perhaps want to check how you've translated the previous occurrences of this title.