How many knights and infantry may have joined the main First Crusade force?

The main force of the First Crusade, which arrived near Constantinople in 1097, is estimated to have included approximately 4,000 mounted knights and 25,000 infantry.12

These massive military forces consisted of four major contingents, alongside a smaller fifth force that had been reduced by shipwreck during its journey. The presence of these troops posed a significant challenge for the Byzantine Emperor Alexius, as the size of the army and the potential for disorder required him to secure oaths of loyalty and territorial restoration from the Crusade leaders.12