HammerFall was formed when guitarist Oscar Dronjak quit Ceremonial Oath and invited Jesper Strömblad ( from In Flames ) to join him as a drummer in a new musical project he had been contemplating for some time .
HammerFall began when guitarist Oscar Dronjak quit Ceremonial Oath and invited Jesper Strömblad from In Flames to join him as a drummer on a new band he had been thinking about for a long time .