Why did king Charles 1 get his head choped off?

The Civil War

ended because parliament won by Oliver Cromwell's new model army.

The Civil War ended because Charles I tried to join the Scots army

and defeat the Roundheads but the Scots give him back to the

Roundheads thinking that Oliver Cromwell was stupid and that

created another battle which was then won by Oliver Cromwell's New

Model Army (Parliament). Parliament deposed King Charles 1st and

placed him on trial because they found him guilty of treason and

they executed him.