Hadith.4662 - Sa'd ibn Sa'd asked Imam Ali ibn Musa Ar-Ridha عليه السلام about whether a child can be breastfed for more than two years.
Imam عليه السلام replied: "Two years."
I asked: "If it exceeds two years, is there any obligation upon the parents because of that?"
Imam عليه السلام said: "No."