Old Dutch naturally evolved into Middle Dutch. The year 1150 is often cited as the time of the discontinuity, but it actually marks a time of profuse Dutch writing and during this period a rich Medieval Dutch literature developed. There was at that time no overarching standard language; Middle Dutch is rather a collective name for a number of closely related dialects whose ancestor was Old Dutch. But they were all mutually intelligible. In fact, since Dutch is a rather conservative language, the various literary works of that time today are often very readable for modern-day speakers.