A man in his 20s has been charged with attempted murder following an assault in Aberdare on Monday.
A 51-year-old man is in a stable condition at Morriston Hospital after he suffered a serious, but not life-threatening, injury to his face.
It is believed he was assaulted in a block of flats in the Heol Keir Hardie area of the valleys town.
South Wales Police said a man in his 20s was being held on remand. Both man are said to know each other.
Detective Inspector Phil Camm said: "The public can be reassured that we have charged somebody with the offence and I would like to thank the community for their cooperation.
"I would also like to inform the local community that those involved in the incident were known to each other."
Anyone with any information about the incident is asked to contact Aberdare CID via 101 or by contacting the independent charity Crimestoppers on 0800 555 111.