Original: Henry quickly gained enough power and support to have himself declared King Henry IV , to imprison King Richard , who died in prison under mysterious circumstances , and to bypass Richard 's seven-year-old heir-presumptive , Edmund de Mortimer .
Simplified: Henry gained enough power and support to have himself declared King Henry IV . He imprisoned King Richard ( who mysteriously died in prison ) and by-passing Richard 's seven-year-old heir presumptive Edmund de Mortimer .