The Song dynasty was under constant

The Song dynasty was under constant military threat, the threat led to a “stimulated centralization of government power” and “improvements in military technology” . Nearly seventy five percent of Song expenditures were spent on military equipment and research. Under threat of northern invasion Song engineers developed gunpowder, incendiary grenades delivered by catapults, and military strategy manuals. The song maintained an army of nearly 1,250,000 men “the government manufactured armaments in huge quantities, arrowheads by the tens of millions per year, amour by tens of thousands” . The massive military expenditures helped spur industrial growth. In 1078 the Song dynasty was mining 125,000 tons of iron ore per year, which is “greater than Great Britain in 1950” . The ability to smelt the ore was “seven hundred years ahead of Europe, very advanced for its time” . Massive military growth and constant spending on industries was one of the factors of the economic boom of the Song dynasty.