Sixteen tablespoons equal one of which unit?

Which 15th-century German cardinal and philosopher wrote "On Learned Ignorance"? Which Elizabethan poet and courtier wrote the sonnet sequence "Astrophel and Stella"? In HIV, what does the "I" stand for? Sixteen of which unit make an avoirdupois pound? Which unit of time is 1/60 of a minute and until 1960 was defined as 1/86,400 of a mean solar day? In 1605, Part One of which Spanish classic was first published? In 1605, which man was discovered under the English Parliament along with barrels of gunpowder? In 1607, which site was settled, becoming the first permanent English colony in the New World?