The 1st of July in (mostly) military history:

552 – Battle of Taginae: Byzantine forces under Narses defeat the Ostrogoths in Italy, and the Ostrogoth king, Totila, is mortally wounded.
1097 – Battle of Dorylaeum: Crusaders led by prince Bohemond of Taranto defeat a Seljuk army led by sultan Kilij Arslan I.
1431 – The Battle of La Higueruela takes place in Granada, leading to a modest advance of the Kingdom of Castile during the Reconquista.
1520 – Spanish conquistadors led by Hernán Cortés fight their way out of Tenochtitlan after nightfall.
1690 – War of the Grand Alliance: Marshal de Luxembourg triumphs over an Anglo-Dutch army at the battle of Fleurus.
1690 – Glorious Revolution: Battle of the Boyne in Ireland (as reckoned under the Julian calendar).
1782 – Raid on Lunenburg: American privateers attack the British settlement of Lunenburg, Nova Scotia.
1841 – Thomas Lempriere and James Clark Ross carve a marker on the Isle of the Dead in Van Diemen's Land to measure tidal variations, one of the earliest surviving benchmarks for sea level rise.
1862 – American Civil War: The Battle of Malvern Hill takes place. It is the last of the Seven Days Battles, part of George B. McClellan's Peninsula Campaign.
1863 – American Civil War: The Battle of Gettysburg begins.
1881 – General Order 70, the culmination of the Cardwell and Childers reforms of the British Army, comes into effect.