You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Genghis_Khan

Context:
The Shah's army was split by diverse internecine feuds and by the Shah's decision to divide his army into small groups concentrated in various cities. This fragmentation was decisive in Khwarezmia's defeats, as it allowed the Mongols, although exhausted from the long journey, to immediately set about defeating small fractions of the Khwarzemi forces instead of facing a unified defense. The Mongol army quickly seized the town of Otrar, relying on superior strategy and tactics. Genghis Khan ordered the wholesale massacre of many of the civilians, enslaved the rest of the population and executed Inalchuq by pouring molten silver into his ears and eyes, as retribution for his actions. Near the end of the battle the Shah fled rather than surrender. Genghis Khan ordered Subutai and Jebe to hunt him down, giving them 20,000 men and two years to do this. The Shah died under mysterious circumstances on a small island within his empire.

Question:
What feature of the Shah's army enable the weary Mongol forces easy early victories?

fragmentation