Justinian wanted to restore the glory of Rome, but many obstacles stood in his way. He brought on talented advisors to help him reform the tax system, the law code, and the military might of the empire. With them he made great strides, but these advisors had very human flaws. His tax collector, John the Cappadocian, centralized tax collection and crushed corruption in his agents, greatly increasing the revenue to the empire - but he also skimmed money off the top to feed his private corruption. Meanwhile, a lawyer named Tribonian took centuries of confusing and even conflicting legal precedents and resolved them into a single code, the Corpis Juris Civilis, which remains the foundation of modern law today. He even made a textbook for students to learn from. But he was also a practicing pagan during an era when Justinian was trying to crack down on pagan rituals. And last, Justinian's chief military commander Belisarius helped the Empire recover its military glory. He defeated the Sassanid Persians in the Battle of Dara, crushing a force of 50,000 men with only 25,000 of his own through clever strategy: he dug a trench to halt their infantry's advance, then baited the Persian cavalry into overextending and sprang a surprise attack on them with Hun mercenaries. Although Belisarius seems to have been an upstanding person, his personal historian Procopius tainted even his clean record. Procopius wrote glowing official histories of the reign of Justinian, but his long lost secret history depicted Justinian as a literal headless demon and Theodora as a debauched monster.