European plate or other heavy armor was initially used in the conquest of the Americas, but it was gradually replaced with other types of armor over time. Conquistadors had difficulty using their heavy armor in the warm, humid climate of Mexico. As they ventured north, this concern became even more important to prevent sickness. It was also difficult to repair iron arms and weapons in early Spanish Mexico due to a lack of facilities and materials. Additionally, Heavy armor can bit a bit, well, heavy. In many engagements, Spanish cavalry were facing infantry troops lacking pikes or other european-like adaptations to their horses. Their mobility, particularly in the border expansion of the 16th and 17th centuries was far more important than heavy protection.