Prior and during the colonial period, native African education in Portuguese East Africa was essentially informal, with initiation rites within tribes the only formal element. Formal education was however provided by Koranic schools in Muslim towns, primarily in the north. These schools focused on knowledge of the Koran and Koranic Arabic. In areas of Portuguese control or influence, schooling was also undeveloped. From the seventeenth century, Portuguese and a small number of Africans received a basic level of education (and inculcation in Portuguese cultural and religious values) at mission schools in Portuguese towns, but many of the children of Portuguese or African princes were instead sent to Goa or Portugal for their education. The small number of educated Africans meant a lack of literate workers, the shortfall being made up in part by Indians.