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:
Middle_Ages

Context:
One of the major developments in the military sphere during the Late Middle Ages was the increased use of infantry and light cavalry. The English also employed longbowmen, but other countries were unable to create similar forces with the same success. Armour continued to advance, spurred by the increasing power of crossbows, and plate armour was developed to protect soldiers from crossbows as well as the hand-held guns that were developed. Pole arms reached new prominence with the development of the Flemish and Swiss infantry armed with pikes and other long spears.

Question:
Along with light cavalry, what military arm was used with increasing frequency in the Late Middle Ages?

infantry