Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) says: The prayers were fifty, the ritual bath (ghusl) for janabah was seven times, and washing urine from clothes was seven times. The Messenger of Allah (peace and blessings be upon him) kept asking for a reduction until the prayers were fixed at five, the ghusl for janabah at once, and washing urine from clothes also remained at once.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 1158