616 Battle of the River Idle
Described by Bede in his Historia Ecclesiastica of 731.
616 Æthelfrith King Bernicia, King Deira killed
12 Oct 633 Battle of Hatfield Chase
Gwynedd and Mercia
Edwin King Bernicia, King Deira  killed
Eadfrith Deira captured
Osfrith Deira killed
634 Battle of Heavenfield
05 Aug 642 Oswestry: Battle of Maserfield
Oswald King Northumbria  killed
654 Battle of Strath Ethairt
Dúnchad mac Conaing King Dál Riata killed
15 Nov 655 Cock Beck: Battle of the Winwaed
Penda King Mercia killed
671 Battle of the Two Rivers
Source: Stephen of Ripon's Vita Sancti Wilfrithi.
A decisive victory of the Northumbrians extending their territory up to the Firth of Forth.
Beornhæth Sub-King Northern Northumbria aka Lothian
Drest VI King Picts
679 Lindsey: Battle of the Trent
A victory for the Mercians. Thereafter the Northumbrians lost their influence south of the Humber, permanently returning the Kingdom of Lindsey to the Mercians.
c 679 Æthelred King Mercia
20 May 685 Dunnichen: Dun Nechtain
Bridei III Picts 
Ecgfrith King Deira, King Northumbria  killed