Which event led to the unification of England and Scotland?

The event that led to the unification of England and Scotland is the Act of Union. Enacted in 1707, this legislation was crucial in creating the Kingdom of Great Britain by uniting the separate kingdoms and parliaments of England and Scotland under a single government. The Act was a response to various political, economic, and social pressures faced by both nations, including the desire for greater stability and the benefits of combined resources and markets.

The other events listed, while significant in their own contexts, did not directly result in the unification of the two kingdoms. The Declaration of Arbroath, for instance, was a statement of Scottish independence that aimed to assert Scotland's sovereignty rather than unify with England. The Glorious Revolution mainly affected the succession of the English throne and established parliamentary sovereignty, having implications primarily in England rather than dealing directly with the unification of these two nations. The Highland Clearances, a later development, involved the forced removal of people from the Scottish Highlands and was a consequence of socio-economic transformations rather than a precursor or facilitator to the political union of Scotland and England.