Complex sentence: He met with ambassadors from the Germanic tribe and offered them land with the Ubii and an alliance against the Suevi, however, Caesar soon became worried that the tribes were delaying until their cavalry could return.
Split into simpler sentences: He met with ambassadors from the Germanic tribe and offered them land with the Ubii and an alliance against the Suevi. However, Caesar soon became worried that the tribes were delaying until their cavalry could return.