One, two, buckle my shoe
Three, four, shut the door
Five, six, pick up sticks
Seven, eight, lay them straight
Nine, ten, a big fat hen
Eleven, twelve, dig and delve
Thirteen, fourteen, maids a’courting
Fifteen, sixteen, maids in the kitchen
Seventeen, eighteen, maids a’waiting
Nineteen, twenty, my platter’s empty …

One theory holds that these nursery rhyme lyrics refer to the plagues that swept Europe in the Middle Ages. “One two buckle my shoe” referred to the special shoes one had to wear to pick up dead bodies, “pick up sticks and lay them straight” referred to the dead bodies one would carry to the mass graves.
(from Wikipedia)
A variant:
One, two, buckle my shoe;
Three, four, knock at the door;
Five, six, pick up sticks;
Seven, eight, lay them straight;
Nine, ten, a good fat hen;
Eleven, twelve, dig and delve;
Thirteen, fourteen, maids a courting;
Fifteen, sixteen, maids a kissing;
Seventeen, eighteen, maids a waiting;
Nineteen, twenty, I’ve had plenty.