| List of illustrations | |
| Abbreviations | |
| Note on transliteration and references | |
| Preface | |
| Acknowledgments | |
| Introduction | 3 |
| 1 | The world's two eyes: Iran, Rome, and the pursuit of world empire | 12 |
| The geographical focus | 12 |
| Iran, the Greeks, and Polytheist Rome | 19 |
| Sasanian universalism | 24 |
| 2 | Polytheist Rome: Toward cultural universalism within empire | 37 |
| Seeds of polytheist universalism | 37 |
| Alexandria | 44 |
| Rome | 45 |
| The third century | 50 |
| Julian and Helios-Mithras | 52 |
| Universalism and Rome's identity | 57 |
| 3 | The Fertile Crescent: Cultural universalism between and beyond empires | 61 |
| The Sabians of Harran | 62 |
| Judaism | 65 |
| Manichaeism | 72 |
| Christianity | 76 |
| 4 | Constantine: Christian empire and crusade | 80 |
| Antecedents of Christian Rome | 80 |
| Constantine's strategy | 85 |
| Empire and Church | 86 |
| Mission | 90 |
| Iran | 93 |
| 5 | The First Byzantine Commonwealth: Interactions of political and cultural universalism | 100 |
| The geographical focus | 101 |
| Iberia and Armenia | 104 |
| Southern Arabia and Ethiopia | 109 |
| Nubia | 116 |
| The Arabs | 119 |
| Christians of Iran and beyond | 121 |
| The politico-cultural entity | 124 |
| 6 | Islam: World empire, then commonwealth | 138 |
| The building of world empire | 138 |
| Empire and religion | 152 |
| The Islamic Commonwealth | 160 |
| Epilogue | 169 |
| Bibliography | 177 |
| Index | 201 |