The South African noticed a man had started following him at around 8.30pm last night, and the stranger struck up a conversation with him.
Soon after, as they walked through the Minster Yard area, the man was repeatedly struck on the head with a rock or cobble.
Witnesses dialled 999 and the pair were found in the Deans Park area.
The victim was taken to York District Hospital for treatment to a serious head injury and damage to his hand.
He has since been released from hospital and his injuries are not believed to be life-threatening.
North Yorkshire Police said officers arrested a 43-year-old man from Tadcaster at the scene on suspicion of attempted murder.
He was taken into police custody and was held for questioning.
Detective Inspector Ian Dyer of York CID said: “This appears to be an unprovoked attack on an elderly man who was enjoying a evening of sightseeing in York.
“We have spoken to a number of witnesses already, but we would still like to speak to anyone else who has not yet come forward.
“I am appealing for anyone who was in the area of York Minster last night to contact us.
“The victim is a tourist and is unfamiliar with York place names.
“Therefore police are appealing for anyone who saw anything untoward in the Minster or Minster Yard or Deans Park area, or anyone who witnessed the actual assault to come forward, if they have not already spoken to police.”
Anyone with information is asked to call York CID on 0845 60 60 247 quoting reference number 12110108652.