What was the period of Little Ice Age?

The term Little Ice Age was first used by François E. Matthes in 1939. It represents a period extending from the 16th to the 19th centuries, however there is no consensus among the scientists on this period. It is generally agreed that there were three minima, beginning about 1650, about 1770, and 1850, each separated by intervals of slight warming. the “Little Ice Age” can only be considered as a modest cooling of the Northern Hemisphere during this period of less than 1°C relative to late 20th century levels.