Haec hasta gravior est quam illa, sed miles eam bene tenet.

They are demonstratives:

• haec = this
• illa = that

In this sentence, both refer to hasta (spear). They must match hasta in:

• gender: feminine
• number: singular
• case: nominative

So:

• haec hasta = this spear
• illa = that one / that spear

Latin often uses demonstratives very precisely, and they agree with the noun they describe.

Because Latin often leaves out a noun when it is obvious from context.

So illa really means:

• illa hasta = that spear

But since hasta was already mentioned, Latin does not need to repeat it. English does the same thing sometimes:

• This spear is heavier than that one.

So illa here means that one, with hasta understood.

Because gravior is the comparative form of gravis (heavy).

• gravis = heavy
• gravior = heavier
• gravissimus / gravissima / gravissimum = heaviest

Since the sentence is comparing two things, Latin uses the comparative:

• Haec hasta gravior est quam illa = This spear is heavier than that one

So gravior does not just describe the spear; it compares it to another spear.

Because gravior is the masculine/feminine nominative singular form, while gravius is the neuter nominative singular form.

Comparative adjectives follow this pattern:

• masculine/feminine nominative singular: -ior
• neuter nominative singular: -ius

Since hasta is feminine singular, the correct form is:

• gravior

If the noun were neuter, then gravius would be possible.

quam means than in a comparison.

So:

• gravior est quam illa = is heavier than that one

A useful thing to notice is that illa is in the same case as the thing being compared with it. Here both are nominative because the comparison is between:

• haec hasta (nominative)
• illa [hasta] (also nominative)

Latin also sometimes uses the ablative of comparison instead of quam, but here the sentence uses the very common comparative + quam pattern.

Because grammatical gender is not the same thing as biological sex.

In Latin, every noun belongs to a grammatical gender:

• masculine
• feminine
• neuter

hasta happens to be a feminine noun. That does not mean the spear is female. It just means that words agreeing with it must use feminine forms, such as:

• haec
• illa
• eam

This is very normal in Latin and many other languages.

eam is the accusative singular feminine form of is, ea, id, meaning her / it in this kind of context.

It is used because the spear is now the direct object of tenet (holds):

• miles eam bene tenet = the soldier holds it well

Why accusative?

Because tenet is a transitive verb, so the thing being held must be in the accusative case.

Why feminine singular?

Because it refers to hasta, which is feminine singular.

Not if the sentence is meant the way it is written.

eam is a more ordinary third-person pronoun: it / her.
illam would mean something more like that one or that woman/that thing, with a stronger demonstrative force.

So:

• eam = it
• illam = that one

Latin often uses is, ea, id for a simple backward reference, where English would just say it.

Grammatically, it is feminine singular, so it could in theory refer to either spear, since both are understood as hasta.

In practice, readers usually take it from the context. Very often it is understood to refer to the more prominent or currently discussed spear, but the form eam by itself does not completely remove ambiguity.

So this is a good example of how Latin, like English, can sometimes rely on context for pronoun reference.

Because miles is a third-declension noun, not a first- or second-declension one.

Its basic form is:

• miles = soldier

Here it is in the nominative singular, so it is the subject of tenet:

• miles ... tenet = the soldier ... holds

A learner might expect a nominative singular masculine noun to end in -us, but that is only common in the second declension. Third-declension nouns have many different endings.

Because bene is an adverb, while bonus is an adjective.

• bonus = good
• bene = well

Since the sentence is describing how the soldier holds the spear, Latin needs an adverb:

• bene tenet = holds well

If you used bonus, you would be describing a noun, not modifying the verb correctly.

It can mean either, depending on context.

Latin present tense often covers both:

• simple present: holds
• progressive present: is holding

So tenet could be understood as either of these in English. Latin does not need a separate form like English is holding in order to express that idea.

No, Latin word order is much more flexible than English word order because the endings show each word’s role.

This sentence is written in a very natural way:

• Haec hasta gravior est quam illa, sed miles eam bene tenet.

But Latin could rearrange parts of it for emphasis. For example, moving eam or bene could change what feels most prominent.

Even so, the given order is helpful and clear:

• haec hasta first, introducing the topic
• gravior est quam illa next, making the comparison
• sed marks the contrast
• miles eam bene tenet gives the second idea

So the word order is not random, but it is not as rigid as in English.

Latin sometimes omits forms of esse (to be), especially in poetry or very compressed style, but in ordinary prose it is often stated clearly.

So:

• Haec hasta gravior est quam illa

is the normal full form: This spear is heavier than that one.

Including est makes the sentence straightforward and standard for a learner.