Meanwhile, reform continued unabated, transforming an absolute monarchy based on traditional relationships of power into a modern, centralized nation state. The process was increasingly under the control of Rama V's European-educated sons. Railways and telegraph lines united previously remote and semi-autonomous provinces. The currency was tied to the gold standard and a modern system of taxation replaced the arbitrary levies and corvee labor of the past. The biggest problem was the shortage of trained civil servants, and many foreigners had to be employed until new schools could be built and Siamese graduates produced. By 1910, when the king died, Siam had become a semi-modern country and continued to escape colonial rule.