The Janapadas were the major kingdoms of Vedic India. By the 6th century B.C. or B.C.E., there were approximately 22 different Janapadas. With the development of iron, as an important metal in parts of Uttar Pradesh and Bihar, the Janapadas became more powerful and turned into Mahajanapadas. There were 16 Mahajanapadas during 600 B.C.E. to 325 B.C.E. in the Indian subcontinent. A few examples of such Mahajanapadas are : Anga, Magadha, Malla, Kosala, Panchala, Matsya, Avanti, etc.