The style of clock called the 'longcase clock' became known as a 'grandfather clock' only in the Victorian era when an American, Henry Clay Work, published a song 'My Grandfather Clock' in 1876.
My grandfather's clock was too large for the shelf,
So it stood ninety years on the floor;
It was taller by half than the old man himself,
Though it weighed not a pennyweight more.
It was bought on the morn of the day that he was born,
And was always his treasure and pride.
But it stopp'd short, Never to go again,
When the old man died...
Once the pendulum was introduced into clock movements, appearing in London from 1658, greater accuracy was possible. It was now worth making clocks with longer running times. The first longcase clock is therefore an evolution of the lantern clock, with a wooden case to protect the weights and pendulum.
A wooden hood was added to cover and protect the movement.
Early longcase clocks were often ebonised, and about 6.5 feet tall. In English clocks, the dial was protected by glass.
There was usually a door at the front, sometimes with a small window, often to show off the later, longer pendulums. These later clocks were often seven feet tall or more, with 10 inch dials.
A separate dial for seconds was added from about 1675.