HAVERHILL — Joining with Masonic lodges across the Commonwealth, Freemasons from Saggahew Lodge at 111 Merrimack St. will open their doors to the public on Saturday, Oct. 21, from 9 a.m. to 3 p.m.

If you’ve ever wondered who the Freemasons are, whether they are the descendants of the Knights Templars, or what the inside of their buildings look like, here’s your chance to find out.

More than 200 lodges will be hosting Open Houses to help the public gain a better understanding of Freemasonry and to demonstrate the positive impact the fraternity has on its members, their families, and their communities. Members will provide tours of their building, talk about Freemasonry’s history, discuss its rituals, signs, and symbols, and explain what they do.

Saggahew Lodge was chartered in 1865 when Merrimack Lodge, Haverhill’s first Masonic Lodge, had a membership that was bursting at its seams. Near the end of the Civil War, there was a great interest in Freemasonry as soldiers returned from war and began working in the shoe factories of Haverhill.

Freemasons trace their roots to the stonemason guilds that built Europe’s cathedrals and castles during the early part of the last millennium. As construction of these buildings declined, they began accepting members from outside their trade.

These new members, influenced by the “Age of Enlightenment,” transformed the organization from a group for builders to one focused on developing the character of its members.

Freemasonry was formally chartered in London in 1717. In 1733 it was organized in Massachusetts, making it the oldest Masonic group in the Western Hemisphere and the third oldest in the world.