diff --git a/CHANGELOG.txt b/CHANGELOG.txt
index 9959792..ffb7e10 100644
--- a/CHANGELOG.txt
+++ b/CHANGELOG.txt
@@ -10,6 +10,9 @@
 - Fix STAC API Query Extension operator names from ne->neq, le->lte, and ge->gte (#120, @philvarner)
 - Better **datetime** parsing/validation by using Pydantic native types and remove `ciso8601` requirement (#131, @eseglem)
 - move datetime validation in `StacCommonMetadata` model definition (#131, @eseglem)
+- use `StacBaseModel` as base model for `Asset` model (#148, @vincentsarago)
+- add `license` in `StacCommonMetadata` model (#147, @vincentsarago)
+- make `limit` optional in `api.Search` model (#150, @vincentsarago)
 
 3.0.0 (2024-01-25)
 ------------------
diff --git a/stac_pydantic/api/search.py b/stac_pydantic/api/search.py
index 62d1e73..c68fd60 100644
--- a/stac_pydantic/api/search.py
+++ b/stac_pydantic/api/search.py
@@ -42,7 +42,7 @@ class Search(BaseModel):
     bbox: Optional[BBox] = None
     intersects: Optional[Intersection] = None
     datetime: Optional[str] = None
-    limit: int = 10
+    limit: Optional[int] = 10
 
     # Private properties to store the parsed datetime values. Not part of the model schema.
     _start_date: Optional[dt] = None
diff --git a/stac_pydantic/shared.py b/stac_pydantic/shared.py
index 126379b..5903cf3 100644
--- a/stac_pydantic/shared.py
+++ b/stac_pydantic/shared.py
@@ -140,6 +140,8 @@ class StacCommonMetadata(StacBaseModel):
     # Date and Time Range
     start_datetime: Optional[UtcDatetime] = None
     end_datetime: Optional[UtcDatetime] = None
+    # Licensing
+    license: Optional[str] = None
     # Provider
     providers: Optional[List[Provider]] = None
     # Instrument
@@ -171,7 +173,7 @@ def validate_start_end(self) -> Self:
         return self
 
 
-class Asset(StacCommonMetadata):
+class Asset(StacBaseModel):
     """
     https://github.com/radiantearth/stac-spec/blob/v1.0.0/item-spec/item-spec.md#asset-object
     """
@@ -185,10 +187,3 @@ class Asset(StacCommonMetadata):
     model_config = ConfigDict(
         populate_by_name=True, use_enum_values=True, extra="allow"
     )
-
-    @model_validator(mode="after")
-    def validate_datetime_or_start_end(self) -> Self:
-        # Overriding the parent method to avoid requiring datetime or start/end_datetime
-        # Additional fields MAY be added on the Asset object, but are not required.
-        # https://github.com/radiantearth/stac-spec/blob/v1.0.0/item-spec/item-spec.md#additional-fields-for-assets
-        return self