# Pax Mongolica **Pax Mongolica** names the roughly century-long period, from the mid-thirteenth to the mid-fourteenth century, in which the [[Mongol Empire]] and its successor khanates held the entire overland Silk Road under a single political authority and made it safe to cross end to end for the first and only time in its history. The security was institutional, not incidental: the **yam** relay-post system with fresh horses and provisioned stations, standardized passports for authorized travellers, suppression of banditry, and a policy of religious tolerance that let merchants of any faith move without harassment. Throughput and transmission speed rose accordingly — gunpowder, printing, the blast furnace, Chinese and Persian astronomy and medicine all moved in this window, and [[Marco Polo]]'s journey and the Florentine merchant Pegolotti's assessment that the road to Cathay was "perfectly safe" both date from it. The same integration carried the [[Black Death]] west in the 1340s, and the khanates' fragmentation and conversion ended the arrangement. > [!note] Stub > Spine stub. Expand: the yam system, the paiza passports, the European and papal embassies, the technology transfers, and the mechanics of the collapse.