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:
History_of_India

Context:
The Kushan Empire expanded out of what is now Afghanistan into the northwest of the subcontinent under the leadership of their first emperor, Kujula Kadphises, about the middle of the 1st century CE. They came of an Indo-European language speaking Central Asian tribe called the Yuezhi, a branch of which was known as the Kushans. By the time of his grandson, Kanishka, they had conquered most of northern India, at least as far as Saketa and Pataliputra, in the middle Ganges Valley, and probably as far as the Bay of Bengal.

Question:
In the middle o what century did the Kushan empire begin?

1st century CE