The idea that religion is a common form of human culture that can be studied, and not just a theological truth to be practiced, has evolved over the centuries. From ancient times, travelers, religious missionaries and historians made observations about the customs and beliefs of "other peoples," though these perceptions were typically driven by considerable religious and cultural bias. Non-biblical religions were even considered by some to be "works of the devil." But knowledge about other cultures gradually advanced, and with that, knowledge about other religions and about the general nature and function of religious language and observance as forms and expressions of culture. By the nineteenth century, reliable translations of non-western scriptures were becoming available and field reports of anthropologists were being published. Academic departments of "the comparative study of religion" began to form with the purpose of gaining an accurate historical understanding of religions and of analyzing and theorizing about this vast, global spectrum of expressions. What emerged was an understanding of religion and types of religion much larger than that supplied by just its conventional biblical or western versions.