In 326 bc, Alexander invaded india. he crossed the river indus and advanced towards taxila.
Ambhi the king pf taxila, welcomed him and his men. then he challenged king porus, ruler of the kingdom between rivers jhelum and chenab and asked for his submission. porus, however, did not oblige. a fierce battle is too well know to every indian, more particularly the dialogue between the two gallant warriors after the defeat of porus.
tradition goes that porus with nine wounds on his body was led a captive before alexander. the greek conqueror should be meted out to him and there came the proud reply from porus as a king treats a king. after the victory over porus, alexander advance forward and defeated kathaioi of sangla and several other tribes surrendered to him. he then wanted to conquer the gangetic nanda dynasty.
the nandas had a powerful army. alexander's solider, who were tried and homesick after many years of wanderings, did not have the courage to face the mighty nandas and thus refused to march forward. consequently alexander had to order retreat and on his way back died at babylon in 323 bc.