What key power did the british parliament hold by 1600

The key power that the British parliament hold by 1600's was the power of tax. It was in the late 1700's that the House of Commons had the sole right to initiate tax measures. It also started back in the thirteenth century where land owners and property owners started to send out representatives to the Parliament about their complaints, their petitions to the king and to accept payments of taxes.

new evidence is discovered.

oversights and errors are corrected,

new technology is applied to evidence.