between him & the Duke of York who was of the right side; if you do not, you had better read some other History, for I shall not be very diffuse in this, meaning by it only to vent my Spleen against, & shew my Hatred to all those people whose parties or principles do not suit with mine, & not to give information.

I have linked to a site that provides "a clear and easy-to-follow survey of the Wars of the Roses including major players and important battles."

The name Wars of the Roses is based on the badges used by the two sides, the red rose for the Lancastrians and the white rose for the Yorkists.

Richard Plantagenet, Duke of York

Richard actually served as both Lieutenant of France and Lieutenant of Ireland for Henry VI. However, he began to oppose Henry's policy on several politcal issues (including the loss of French lands won by Henry V). Finally, in 1455 fighting erupted at the battle of First St. Albans where Richard defeated the Lancastrian forces.

During Henry's fits of mental illness, Richard served as Protector. (That like a de-facto king or regent? So at least he job experience to be king.)

However, he died in 1460 at the battle of Wakefield.