The Song dynasty was the beginning of modern China. This era was marked by a flourishing economy, a deep distinctively Chinese culture, and technological revolutions. From the beginning to the end the Song dynasty was under a constant threat from northern tribes that coveted the wealth of the Song. The powerful states that surrounded the Song dynasty crushed all hopes for expansion. The Song was forced to focus on developing their own country instead of conquering others. Without the opportunity to expand and a military threat on the borders the Song were forced to either flourish or perish. The hostile states that looked enviously on the wealth and prosperity of the Song were a main factor in the economic and cultural greatness that they desired.