Why did Richard usurp the throne?

Why did he usurp?

If Edward V was crowned within weeks of being brought to London, Richard of Gloucester was in serious trouble. If he did not become protector, he may have been at the mercy of the new king and Woodville relatives, who would surely object to the arrest of Rivers, Grey and Vaughan. 

All Richard's power in the North, given to him by his grateful brother Edward IV, could have been taken away from him by an ungrateful nephew!

All the problems associated with Edward V's childhood- treachery, betrayal and turbulence- might return to unseat him and to end the quiet of his Kingdom.

However..

If Richard became protector, he would be forced to give up his power in a few years time anyway and then be at the mercy of his enemies. 

Therefore..

Richard chose to usurp the throne.

Only as king, he thought, he could be secure.

To summarise why Richard usurped:

• He may have been at mercy of the new King and Woodville relatives.
• If the Woodvilles had power, they would question Richard's decision to arrest Rivers, Vaughan and Grey.
• Richard's power in the North could be taken away by Edward V.
• Perhaps Richard thought Edward would only cause more turbulence and continue the Wars of the Roses.
•  If he was protector, he would have to give up his power as soon as Edward was old enough to rule independently.

A childhood in the Wars of the Roses.

 When you take into consideration that Richard was a child of the turbulent Wars of the Roses, we can understand his need for security more clearly. At the age of six his father had been named as heir to the throne of Henry VI by an Act of Parliament 

'The Act of Accord'

1640

Just weeks later due to the power struggle between the rival families, Richard's father and brother were killed and he was forced into exile. 

Weeks later, his elder brother was crowned

King Edward IV

These events made it clear that political fortunes were subject to rapid change.

The rest of the 1460's

The rest of the 1460s showed that no one could be trusted when Clarence, brother of Edward IV and Richard, sided with the enemy (Richard Neville, Earl of Warwick) to overthrow Edward IV in 1470.

This resulted in a second period of exile for Richard.

In this context it is perhaps understandable that he panicked in 1483 when Edward IV died and rumours circulated that the Woodvilles were plotting against Richard. 

To conclude:

Richard foresaw his own downfall unless he acted decisively. 

And decisively was how he acted.