Musnad Ahmad 149:1

Waki’ narrated to us, from Sufyan, from Yahya ibn Sa’id, from Muhammad ibn Ibrahim al-Taymi, from Abu Hadrad al-Aslami, that he came to the Prophet, peace and blessings of Allah be upon him, seeking a legal opinion regarding the dowry of a woman. He said: "How much did you give her as a dowry?" He said: "Two hundred dirhams." He said: "If you were scooping from Buthan, you would not have added more."