Who are they, Rum?

Prophet Muhammad (SAW) has prophesied that:

'You will make an alliance with Rum'.  

The question is - who are they, the Rum?

Is this Rome of Italy?

Here is article written by Sheikh Imran N Hosein answering the above question:

Question: When Israel Wages Her Big Wars Would That Be The Time When Muslim Will Make An Alliance With Rum? Is This Rome, Italy?

"Nabi Muhammad (SA) has prophesised that

'You will make an alliance with Rum'.

Indeed there is a... Surah of the Qur'an which is entitled Surah Ar-Rum. And in that Surah, in the first Ayah, Allah speaks about Rum being defeated. If you believe that Allah (SWT) was referring to a city in Italy then you should buy a one way ticket to Disneyland.
When the Qur'an says that Rum has been defeated, was referring to a city in Italy called Rome? Oh come one, what kind of scholarship is that? And when the Qur'an refers to Rum you translate it as Romans? Is that the correct translation, Romans?

Rum in the Qur'an is easy to identify. It is the 'Eastern Orthodox Christian Church'; which had established the Byzantine Empire with Constantinople as its capital...
Prophet (SA) said 'You will make an alliance with Rum'. The Byzantine Empire has disappeared today, but the 'Eastern Orthodox Christian Church' has not. If we want to find Rum, where is the 'Eastern Orthodox Christian Church' today?

Answer, the headquarters is now in Russia. If I am wrong I invite you to correct me. And so when the Prophet (SA) said, 'You will make an alliance with Rum', my answer is its going to be an alliance with Russia. .." 

Written by Imran N. Hosein 

Source: http://www.imranhosein.org/faq/28-muslim-village/326-rum-rome.html